theming: Allow themes to use different thumbnail image sizes

This change makes thumbnail image sizes more flexible by explicitly
stating the particular image size is a thumbnail. And each thumbnail
image size can have different squared settings.

On the theme side it's now mandatory to specify which thumbnail size
to use (if applicable). This allows us to have different thumbnail styles
for index and album pages.

This commit also removes the <squared_thumbnails> tag from setup.xml
file but retains fallback for ver. 1 setup.xml files.

9 files changed, 184 insertions, 147 deletions

diff --git a/sample/src/setup.xml b/sample/src/setup.xml
index 327659d..6487f60 100644
--- a/sample/src/setup.xml
+++ b/sample/src/setup.xml
@@ -40,12 +40,6 @@
     <!--    - override with <fullsize/> for album or for separate image  -->
 <!--    <nofullsize />  -->
 
-    <!--  Make thumbnails squared, crop in different ways:               -->
-    <!--    none   - no squared thumbnails, retain previous behaviour (default)  -->
-    <!--    simple - crop from center, shave 5% from borders             -->
-    <!--    ... more to come! (looking for a fast and clever algorithm)  -->
-    <squared_thumbnails type="none" />
-
     <!--  autorotate input images according to EXIF information, unless   -->
     <!--  provided in the album source file (copy mode)  (default = yes)  -->
     <autorotate value="yes" />
diff --git a/src/cgg.c b/src/cgg.c
index ea493ac..be882b1 100644
--- a/src/cgg.c
+++ b/src/cgg.c
@@ -168,7 +168,7 @@ main (int argc, char* argv[])
     }
   }
 
-  if (! validate_design_setup (setup->design))
+  if (! validate_design_setup (setup))
     return -7;
 
   templates_basedir = find_design_directory (setup);
diff --git a/src/generators.c b/src/generators.c
index a2f7a65..3d04ad6 100644
--- a/src/generators.c
+++ b/src/generators.c
@@ -44,21 +44,6 @@
 
 #define BUFFER_SIZE  65536    /*  line cannot be longer than this  */
 
-static TImageSize *
-find_image_size_for_name (TGallerySetup *setup, const gchar *name)
-{
-  GList *l;
-  TImageSize *image_size;
-
-  for (l = g_list_first (setup->design->image_sizes); l; l = g_list_next (l)) {
-    image_size = l->data;
-    g_assert (image_size != NULL);
-    if (g_ascii_strcasecmp (name, image_size->name) == 0)
-      return image_size;
-  }
-  return NULL;
-}
-
 
 static void
 get_image_paths (TGallerySetup *setup,
@@ -72,7 +57,6 @@ get_image_paths (TGallerySetup *setup,
                  gchar **page_img_dst)
 {
   gboolean nofullsize;
-  gboolean is_thumbnail;
   gboolean is_preview;
   gboolean is_original;
   gchar *s1, *s2, *s3;
@@ -87,23 +71,23 @@ get_image_paths (TGallerySetup *setup,
     *page_img_dst = NULL;
   preview_image_size = NULL;
 
-  /*  ignore combinations that are not valid  */
   nofullsize = IS_NOFULLSIZE (item, items, setup);
-  is_thumbnail = g_ascii_strcasecmp ("thumbnail", image_size->name) == 0;
   is_preview = g_ascii_strcasecmp ("preview", image_size->name) == 0;
   is_original = g_ascii_strcasecmp ("original", image_size->name) == 0;
-  if ((items->type == GALLERY_TYPE_INDEX && ! is_thumbnail) ||
-      (is_thumbnail && item->hidden) ||
-      (is_thumbnail && items->type == GALLERY_TYPE_INDEX && (item->thumbnail == NULL || strlen (item->thumbnail) == 0)))
+
+  /*  ignore combinations that are not valid  */
+  if ((items->type == GALLERY_TYPE_INDEX && ! image_size->is_thumbnail) ||
+      (image_size->is_thumbnail && item->hidden) ||
+      (image_size->is_thumbnail && items->type == GALLERY_TYPE_INDEX && (item->thumbnail == NULL || strlen (item->thumbnail) == 0)))
     return;
 
   /*  nofullsize specified, fall back to preview if available  */
   if (is_original && nofullsize)
-    preview_image_size = find_image_size_for_name (setup, "preview");
+    preview_image_size = lookup_image_size_for_name (setup, "preview");
   target_image_dir = g_strdup_printf ("%s%s", TARGET_IMAGE_DIR_PREFIX, preview_image_size ? preview_image_size->name : image_size->name);
 
   /*  Thumbnail special case  */
-  if (is_thumbnail) {
+  if (image_size->is_thumbnail) {
     s1 = NULL;
     if (items->type == GALLERY_TYPE_INDEX) {
       s1 = item->thumbnail;
@@ -152,7 +136,8 @@ metadata_apply_overrides (ExifData *exif_data,
                           TGallerySetup *setup,
                           TPathInfo *path_info,
                           TAlbum *items,
-                          TIndexItem *item)
+                          TIndexItem *item,
+                          TImageSize *image_size)
 {
   g_return_if_fail (exif_data != NULL);
 
@@ -170,8 +155,7 @@ metadata_apply_overrides (ExifData *exif_data,
   if (setup->write_supplied_exif && item->metadata_external_exif)
     exif_data->external_exif_data = g_path_is_absolute (item->metadata_external_exif) ? g_strdup (item->metadata_external_exif) : g_build_filename (path_info->src_dir, item->metadata_external_exif, NULL);
 
-  exif_data->squared_thumbnail_type = setup->squared_thumbnail_type;
-
+  exif_data->squared_thumbnail = image_size->is_thumbnail && image_size->squared_thumb;
   exif_data->thumbnail_crop_hint = get_prop_int (items, item, PROP_THUMB_CROP_HINT, CROP_HINT_UNDEFINED);
 }
 
@@ -188,7 +172,6 @@ generate_image (TGallerySetup *setup,
                 gboolean query_update)
 {
   gboolean res;
-  gboolean is_thumbnail;
   gboolean is_preview;
   gboolean is_original;
   gchar *img_src;
@@ -206,7 +189,6 @@ generate_image (TGallerySetup *setup,
     image_size = l->data;
 
     /*  TODO: this is too specific  */
-    is_thumbnail = g_ascii_strcasecmp ("thumbnail", image_size->name) == 0;
     is_preview = g_ascii_strcasecmp ("preview", image_size->name) == 0;
     is_original = g_ascii_strcasecmp ("original", image_size->name) == 0;
 
@@ -224,13 +206,13 @@ generate_image (TGallerySetup *setup,
     }
 
     exif_data = exif_data_new_empty ();
-    metadata_apply_overrides (exif_data, setup, path_info, items, item);
+    metadata_apply_overrides (exif_data, setup, path_info, items, item, image_size);
 
     /*  Do something when required  */
     res = res || needs_update (img_src, img_dst);
     if (! query_update) {
       /*  Copy the source file  */
-      if (image_size->no_resize && ((is_preview && item->preview) || is_original)) {
+      if (! image_size->is_thumbnail && image_size->no_resize && ((is_preview && item->preview) || is_original)) {
         if (! copy_file (img_src, img_dst))
           log_error ("  Error copying image %s to %s\n", img_src, img_dst);
       }
@@ -240,32 +222,33 @@ generate_image (TGallerySetup *setup,
         if (img_w > 0 && img_h > 0) {
           stats_images_inc ();
 
-          /*  Only the "preview" size is affected by deprecated item and album overrides  */
-          if (is_preview) {
-            tmpw = get_prop_int (items, item, PROP_WIDTH, img_w);
-            tmph = get_prop_int (items, item, PROP_HEIGHT, img_h);
-            calculate_sizes (tmpw, tmph, &img_w, &img_h);
-          }
-          if (is_thumbnail && setup->squared_thumbnail_type != THUMBNAIL_SQUARE_TYPE_NONE)
-            tmpw = tmph = image_size->square_size;
-          else
-          /*  Calculate sizes  */
-          if (img_w > img_h) {
-            tmpw = image_size->landscape_width;
-            tmph = image_size->landscape_height;
+          if (image_size->is_thumbnail && image_size->squared_thumb)
+            img_w = img_h = image_size->square_size;
+          else {
+            /*  Only the "preview" size is affected by deprecated item and album overrides  */
             if (is_preview) {
-              tmpw = get_prop_int (items, item, PROP_LANDSCAPE_W, tmpw);
-              tmph = get_prop_int (items, item, PROP_LANDSCAPE_H, tmph);
+              tmpw = get_prop_int (items, item, PROP_WIDTH, img_w);
+              tmph = get_prop_int (items, item, PROP_HEIGHT, img_h);
+              calculate_sizes (tmpw, tmph, &img_w, &img_h);
             }
-          } else {
-            tmpw = image_size->portrait_width;
-            tmph = image_size->portrait_height;
-            if (is_preview) {
-              tmpw = get_prop_int (items, item, PROP_PORTRAIT_W, tmpw);
-              tmph = get_prop_int (items, item, PROP_PORTRAIT_H, tmph);
+            /*  Calculate sizes  */
+            if (img_w > img_h) {
+              tmpw = image_size->landscape_width;
+              tmph = image_size->landscape_height;
+              if (is_preview) {
+                tmpw = get_prop_int (items, item, PROP_LANDSCAPE_W, tmpw);
+                tmph = get_prop_int (items, item, PROP_LANDSCAPE_H, tmph);
+              }
+            } else {
+              tmpw = image_size->portrait_width;
+              tmph = image_size->portrait_height;
+              if (is_preview) {
+                tmpw = get_prop_int (items, item, PROP_PORTRAIT_W, tmpw);
+                tmph = get_prop_int (items, item, PROP_PORTRAIT_H, tmph);
+              }
             }
+            calculate_sizes (tmpw, tmph, &img_w, &img_h);
           }
-          calculate_sizes (tmpw, tmph, &img_w, &img_h);
           /*  Calculate quality  */
           if (is_preview)
             quality = get_prop_int (items, item, PROP_QUALITY, image_size->quality);
@@ -273,14 +256,14 @@ generate_image (TGallerySetup *setup,
             quality = image_size->quality;
 
           /*  Perform resize and strip  */
-          if (! resize_image (img_src, img_dst, img_w, img_h, quality, is_thumbnail, setup->autorotate, exif_data))
+          if (! resize_image (img_src, img_dst, img_w, img_h, quality, image_size->is_thumbnail, setup->autorotate, exif_data))
             log_error ("  Error resizing image %s\n", img_src);
         } else {
           log_error ("generate_image: image %s sizes are %lux%lu\n", img_src, img_w, img_h);
         }
       }
     }
-    if (! is_thumbnail) {
+    if (! image_size->is_thumbnail) {
       modify_exif (img_dst, exif_data, setup->erase_exif_thumbnail, setup->strip_xmp);
     }
 
@@ -491,8 +474,9 @@ write_html_album (TGallerySetup *setup,
 
   /*  Theming  */
   /* TODO: "image_size" will be used for album themes showing pictures inpage */
-  image_size = find_image_size_for_name (setup, theme->album_image_size);
-  thumb_image_size = find_image_size_for_name (setup, "thumbnail");
+  image_size = lookup_image_size_for_name (setup, theme->album_image_size);
+  thumb_image_size = lookup_image_size_for_name (setup, items->type == GALLERY_TYPE_ALBUM ? theme->album_thumb_size : theme->index_thumb_size);
+  g_assert (thumb_image_size != NULL);
 
   /*  Setup block parser  */
   block_parser_register_key (block_parser, "IMG_LIST", "IMG_LIST");
@@ -554,7 +538,7 @@ write_html_album (TGallerySetup *setup,
               if (s2 != NULL)
                 get_image_sizes (s2, &img_thumb_w, &img_thumb_h, setup->autorotate);
 
-              if (setup->squared_thumbnail_type != THUMBNAIL_SQUARE_TYPE_NONE || img_thumb_w == img_thumb_h)
+              if (thumb_image_size->squared_thumb || img_thumb_w == img_thumb_h)
                 s1 = "IMG_LIST_SQUARED";
               else
                 s1 = (img_thumb_h > img_thumb_w) ? "IMG_LIST_PORTRAIT" : "IMG_LIST_LANDSCAPE";
@@ -783,9 +767,9 @@ write_html_image (TGallerySetup *setup,
   /*  If currently processed picture size is original, disable fullsize tags  */
   theme_size_is_original = g_ascii_strcasecmp (theme->picture_image_size, "original") == 0;
   /*  Original size is needed for several things, like EXIF and IPTC metadata  */
-  image_size = find_image_size_for_name (setup, "original");
+  image_size = lookup_image_size_for_name (setup, "original");
   get_image_paths (setup, parent_items, item, item_index, path_info, image_size, &img_orig_src, &img_orig_dst, &img_orig_dst_page);
-  image_size = find_image_size_for_name (setup, theme->picture_image_size);
+  image_size = lookup_image_size_for_name (setup, theme->picture_image_size);
   get_image_paths (setup, parent_items, item, item_index, path_info, image_size, NULL, &img_dst, &img_dst_page);
   imgname = g_path_get_basename (img_dst);
   if (next_item && setup->preload)
@@ -819,7 +803,7 @@ write_html_image (TGallerySetup *setup,
     */
   }
   if (exif != NULL)
-    metadata_apply_overrides (exif, setup, path_info, parent_items, item);
+    metadata_apply_overrides (exif, setup, path_info, parent_items, item, image_size);
   /*  Test for basic EXIF keys presence  */
   if (exif != NULL && exif_has_key (exif, EXIF_APERTURE) &&
                       exif_has_key (exif, EXIF_FOCAL_LENGTH) &&
diff --git a/src/job-manager.c b/src/job-manager.c
index fd41550..1bf9c5c 100644
--- a/src/job-manager.c
+++ b/src/job-manager.c
@@ -301,8 +301,8 @@ build_tree (TGallerySetup *setup,
   for (l = g_list_first (setup->design->image_sizes); l; l = g_list_next (l)) {
     image_size = l->data;
     g_assert (image_size != NULL);
-    /*  We don't allow having single pictures in index pages at the moment, might change in the future  */
-    if (items->type != GALLERY_TYPE_INDEX || g_ascii_strcasecmp (image_size->name, "thumbnail") == 0) {
+    /*  We don't allow having pictures in index pages at the moment, might change in the future  */
+    if (items->type != GALLERY_TYPE_INDEX || image_size->is_thumbnail) {
       s1 = g_strdup_printf ("%s%s", TARGET_IMAGE_DIR_PREFIX, image_size->name);
       s2 = g_build_path (G_DIR_SEPARATOR_S, path_info->dest_dir, s1, NULL);
       g_free (s1);
diff --git a/src/jpeg-utils.cpp b/src/jpeg-utils.cpp
index 5c0269a..a552e69 100644
--- a/src/jpeg-utils.cpp
+++ b/src/jpeg-utils.cpp
@@ -481,33 +481,29 @@ resize_image (const gchar *src, const gchar *dst,
   {
     /*  Process thumbnail if required  */
     if (thumbnail) {
-      switch (exif->squared_thumbnail_type) {
-        case THUMBNAIL_SQUARE_TYPE_SIMPLE:
-          w = MagickGetImageWidth (magick_wand);
-          h = MagickGetImageHeight (magick_wand);
-          amount = MAX (w, h) * SQUARED_SIMPLE_SHAVE_AMOUNT / 100;
-          amount = MIN (w - 2*amount, h - 2*amount);
-          switch (exif->thumbnail_crop_hint) {
-            case CROP_HINT_UNDEFINED:
-            case CROP_HINT_CENTER:
-              MagickCropImage (magick_wand, amount, amount, (w - amount) / 2, (h - amount) / 2);
-              break;
-            case CROP_HINT_LEFT:
-              MagickCropImage (magick_wand, amount, amount, 0, (h - amount) / 2);
-              break;
-            case CROP_HINT_RIGHT:
-              MagickCropImage (magick_wand, amount, amount, w - amount, (h - amount) / 2);
-              break;
-            case CROP_HINT_TOP:
-              MagickCropImage (magick_wand, amount, amount, (w - amount) / 2, 0);
-              break;
-            case CROP_HINT_BOTTOM:
-              MagickCropImage (magick_wand, amount, amount, (w - amount) / 2, h - amount);
-              break;
-          }
-          break;
-        default:
-          break;
+      if (exif->squared_thumbnail) {
+        w = MagickGetImageWidth (magick_wand);
+        h = MagickGetImageHeight (magick_wand);
+        amount = MAX (w, h) * SQUARED_SIMPLE_SHAVE_AMOUNT / 100;
+        amount = MIN (w - 2*amount, h - 2*amount);
+        switch (exif->thumbnail_crop_hint) {
+          case CROP_HINT_UNDEFINED:
+          case CROP_HINT_CENTER:
+            MagickCropImage (magick_wand, amount, amount, (w - amount) / 2, (h - amount) / 2);
+            break;
+          case CROP_HINT_LEFT:
+            MagickCropImage (magick_wand, amount, amount, 0, (h - amount) / 2);
+            break;
+          case CROP_HINT_RIGHT:
+            MagickCropImage (magick_wand, amount, amount, w - amount, (h - amount) / 2);
+            break;
+          case CROP_HINT_TOP:
+            MagickCropImage (magick_wand, amount, amount, (w - amount) / 2, 0);
+            break;
+          case CROP_HINT_BOTTOM:
+            MagickCropImage (magick_wand, amount, amount, (w - amount) / 2, h - amount);
+            break;
+        }
       }
       MagickThumbnailImage (magick_wand, size_x, size_y);
       /*  FIXME: this strips image ICC profile, should do proper conversion first  */
diff --git a/src/jpeg-utils.h b/src/jpeg-utils.h
index 6b92b3d..3700d66 100644
--- a/src/jpeg-utils.h
+++ b/src/jpeg-utils.h
@@ -57,7 +57,7 @@ typedef struct {
   double override_aperture;
   double override_focal_length;
   gchar *external_exif_data;
-  ThumbnailSquareType squared_thumbnail_type;
+  gboolean squared_thumbnail;
   TCropHint thumbnail_crop_hint;
 } ExifData;
 
diff --git a/src/setup.c b/src/setup.c
index e0741c5..637a1b3 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -82,7 +82,6 @@ TGallerySetup *
 parse_setup_xml (const gchar *filename)
 {
   TXMLFile *xml;
-  gchar *s;
   TGallerySetup *setup;
 
   xml = xml_parser_load (filename);
@@ -106,13 +105,6 @@ parse_setup_xml (const gchar *filename)
   setup->nofullsize = xml_file_get_node_present (xml, "/gallery_setup/images/nofullsize");
   setup->autorotate = xml_file_get_node_attribute_boolean_with_default (xml, "/gallery_setup/images/autorotate", "value", TRUE);
 
-  s = xml_file_get_node_attribute (xml, "/gallery_setup/images/squared_thumbnails", "type");
-  if (s && g_ascii_strcasecmp (s, "simple") == 0)
-    setup->squared_thumbnail_type = THUMBNAIL_SQUARE_TYPE_SIMPLE;
-  else
-    setup->squared_thumbnail_type = THUMBNAIL_SQUARE_TYPE_NONE;
-  g_free (s);
-
   /*  meta section  */
   setup->meta_author = xml_file_get_node_value (xml, "/gallery_setup/meta/author/text()");
   setup->meta_author_email = xml_file_get_node_value (xml, "/gallery_setup/meta/author_email/text()");
@@ -184,11 +176,33 @@ parse_design_setup_xml (const gchar *filename)
   /*  image_sizes section  */
   count = xml_file_node_get_children_count (xml, "/design_setup/image_sizes/size");
   for (i = 0; i < count; i++) {
+    s = g_strdup_printf ("/design_setup/image_sizes/size[%d]", i + 1);
+    s2 = xml_file_get_node_attribute (xml, s, "name");
+    if (s2 == NULL || strlen (s2) == 0) {
+      fprintf (stderr, "design setup error: image size #%d defined with no name, ignoring\n", i + 1);
+      g_free (s);
+      g_free (s2);
+      continue;
+     }
+
     image_size = g_malloc0 (sizeof (TImageSize));
     design->image_sizes = g_list_append (design->image_sizes, image_size);
 
-    s = g_strdup_printf ("/design_setup/image_sizes/size[%d]", i + 1);
-    image_size->name = xml_file_get_node_attribute (xml, s, "name");
+    image_size->name = s2;
+    s2 = xml_file_get_node_attribute (xml, s, "type");
+    if (s2 && g_ascii_strcasecmp (s2, "thumbnail") == 0)
+      image_size->is_thumbnail = TRUE;
+    g_free (s2);
+    if (image_size->is_thumbnail) {
+      s2 = xml_file_get_node_attribute (xml, s, "style");
+      if (s2 && g_ascii_strcasecmp (s2, "squared") == 0)
+        image_size->squared_thumb = TRUE;
+      g_free (s2);
+    }
+    g_free (s);
+
+    s = g_strdup_printf ("/design_setup/image_sizes/size[%d]/no_resize", i + 1);
+    image_size->no_resize = xml_file_get_node_present (xml, s);
     g_free (s);
 
     s = g_strdup_printf ("/design_setup/image_sizes/size[%d]/landscape", i + 1);
@@ -231,6 +245,9 @@ parse_design_setup_xml (const gchar *filename)
     s = g_strdup_printf ("/design_setup/theme[%d]/index/target_filename/text()", i + 1);
     theme->index_filename = xml_file_get_node_value_with_default (xml, s, DEFAULT_INDEX_FILENAME);
     g_free (s);
+    s = g_strdup_printf ("/design_setup/theme[%d]/index/thumbnail_size/text()", i + 1);
+    theme->index_thumb_size = xml_file_get_node_value (xml, s);
+    g_free (s);
 
     s = g_strdup_printf ("/design_setup/theme[%d]/album/template/text()", i + 1);
     theme->album_template = xml_file_get_node_value (xml, s);
@@ -241,6 +258,9 @@ parse_design_setup_xml (const gchar *filename)
     s = g_strdup_printf ("/design_setup/theme[%d]/album/picture_size/text()", i + 1);
     theme->album_image_size = xml_file_get_node_value (xml, s);
     g_free (s);
+    s = g_strdup_printf ("/design_setup/theme[%d]/album/thumbnail_size/text()", i + 1);
+    theme->album_thumb_size = xml_file_get_node_value (xml, s);
+    g_free (s);
     s = g_strdup_printf ("/design_setup/theme[%d]/album/protected_thumbnail/text()", i + 1);
     theme->album_protected_thumbnail = xml_file_get_node_value (xml, s);
     g_free (s);
@@ -292,6 +312,7 @@ makeup_legacy_design (const gchar *filename)
   TGalleryDesign *design;
   TImageSize *image_size;
   TGalleryDesignTheme *theme;
+  gboolean squared_thumbs;
   int i;
   const gchar * image_sizes[3] = { "thumbnail", "preview", "original" };
 
@@ -307,6 +328,12 @@ makeup_legacy_design (const gchar *filename)
     g_free (s);
   }
 
+  squared_thumbs = FALSE;
+  s = xml_file_get_node_attribute (xml, "/gallery_setup/images/squared_thumbnails", "type");
+  if (s && g_ascii_strcasecmp (s, "simple") == 0)
+    squared_thumbs = TRUE;
+  g_free (s);
+
   /*  image_sizes section  */
   for (i = 0; i < G_N_ELEMENTS (image_sizes); i++) {
     image_size = g_malloc0 (sizeof (TImageSize));
@@ -318,7 +345,9 @@ makeup_legacy_design (const gchar *filename)
     image_size->portrait_height = xml_file_get_node_attribute_long_with_default (xml, s, "portrait_h", 0);
     image_size->square_size = xml_file_get_node_attribute_long_with_default (xml, s, "square", 0);
     image_size->quality = xml_file_get_node_attribute_long_with_default (xml, s, "quality", -1);
-    image_size->no_resize = (i == G_N_ELEMENTS (image_sizes) - 1);
+    image_size->no_resize = (i != 0);
+    image_size->is_thumbnail = (i == 0);
+    image_size->squared_thumb = (i == 0) && squared_thumbs;
     g_free (s);
     design->image_sizes = g_list_append (design->image_sizes, image_size);
   }
@@ -333,6 +362,7 @@ makeup_legacy_design (const gchar *filename)
     theme->index_template = g_strdup ("template_index.html");
   }
   theme->index_filename = xml_file_get_node_value_with_default (xml, "/gallery_setup/templates/index_file/text()", DEFAULT_INDEX_FILENAME);
+  theme->index_thumb_size = g_strdup (image_sizes[0]);
 
   theme->album_template = xml_file_get_node_value (xml, "/gallery_setup/templates/album/text()");
   if (g_strcmp0 (theme->album_template, "template-album.tmpl") == 0) {
@@ -341,6 +371,7 @@ makeup_legacy_design (const gchar *filename)
   }
   theme->album_filename = xml_file_get_node_value_with_default (xml, "/gallery_setup/templates/index_file/text()", DEFAULT_INDEX_FILENAME);
   theme->album_image_size = g_strdup (image_sizes[1]);
+  theme->album_thumb_size = g_strdup (image_sizes[0]);
   theme->album_protected_thumbnail = NULL;
 
   theme->picture_template = xml_file_get_node_value (xml, "/gallery_setup/templates/photo/text()");
@@ -365,69 +396,68 @@ makeup_legacy_design (const gchar *filename)
   return design;
 }
 
-
-static gboolean
-lookup_image_size (TGalleryDesign *design, const gchar *image_size_name)
+/*
+ *   lookup_image_size_for_name: looks up an image size record for given image size name
+ */
+TImageSize *
+lookup_image_size_for_name (TGallerySetup *setup, const gchar *name)
 {
   GList *l;
   TImageSize *image_size;
 
-  g_return_val_if_fail (image_size_name != NULL, FALSE);
-  g_return_val_if_fail (strlen (image_size_name) > 0, FALSE);
-
-  for (l = g_list_first (design->image_sizes); l; l = g_list_next (l)) {
+  for (l = g_list_first (setup->design->image_sizes); l; l = g_list_next (l)) {
     image_size = l->data;
     g_assert (image_size != NULL);
-    if (image_size->name == NULL || strlen (image_size->name) == 0) {
-      fprintf (stderr, "design validation warning: image size %p defined with no name\n", image_size);
-      continue;
-    }
-    if (image_size->landscape_width <= 0 || image_size->landscape_height <= 0 ||
-        image_size->portrait_width <= 0 || image_size->portrait_height <= 0) {
-      fprintf (stderr, "design validation warning: image size %s defined with zero sized element\n", image_size->name);
-      continue;
-    }
-    if (g_ascii_strcasecmp (image_size_name, image_size->name) == 0)
-      return TRUE;
+    if (g_ascii_strcasecmp (name, image_size->name) == 0)
+      return image_size;
   }
-
-  return FALSE;
+  return NULL;
 }
 
 /*
  *   validate_design_setup: validate design.xml file setup
  */
 gboolean
-validate_design_setup (TGalleryDesign *design)
+validate_design_setup (TGallerySetup *setup)
 {
   GList *l;
+  TImageSize *image_size;
   TGalleryDesignTheme *theme;
 
   /*  check for version match  */
-  if (! SETUP_IS_NATIVE (design)) {
+  if (! SETUP_IS_NATIVE (setup->design)) {
     fprintf (stderr, "design validation error: version mismatch\n");
     return FALSE;
   }
 
   /*  validate sizes  */
-  if (g_list_length (design->image_sizes) == 0) {
+  if (g_list_length (setup->design->image_sizes) == 0) {
     fprintf (stderr, "design validation error: no image size defined\n");
     return FALSE;
   }
-  if (! lookup_image_size (design, "original")) {
-      fprintf (stderr, "design validation error: mandatory \"original\" image size not defined\n");
-      return FALSE;
+  if (lookup_image_size_for_name (setup, "original") == NULL) {
+    fprintf (stderr, "design validation error: mandatory \"original\" image size not defined\n");
+    return FALSE;
+  }
+  for (l = g_list_first (setup->design->image_sizes); l; l = g_list_next (l)) {
+    image_size = l->data;
+    g_assert (image_size != NULL);
+    if (image_size->landscape_width <= 0 || image_size->landscape_height <= 0 ||
+        image_size->portrait_width <= 0 || image_size->portrait_height <= 0) {
+      fprintf (stderr, "design validation warning: image size %s defined with zero sized element\n", image_size->name);
+      continue;
     }
+  }
 
   /*  validate themes  */
-  if (g_list_length (design->themes) == 0) {
+  if (g_list_length (setup->design->themes) == 0) {
     fprintf (stderr, "design validation error: no theme defined\n");
     return FALSE;
   }
-  for (l = g_list_first (design->themes); l; l = g_list_next (l)) {
+  for (l = g_list_first (setup->design->themes); l; l = g_list_next (l)) {
     theme = l->data;
     g_assert (theme != NULL);
-    if (theme->album_image_size && ! lookup_image_size (design, theme->album_image_size)) {
+    if (theme->album_image_size && lookup_image_size_for_name (setup, theme->album_image_size) == NULL) {
       fprintf (stderr, "design validation error: theme-defined image size '%s' not found\n", theme->album_image_size);
       return FALSE;
     }
@@ -435,10 +465,32 @@ validate_design_setup (TGalleryDesign *design)
       fprintf (stderr, "design validation error: theme does not define mandatory picture size argument\n");
       return FALSE;
     }
-    if (! lookup_image_size (design, theme->picture_image_size)) {
+    if (lookup_image_size_for_name (setup, theme->picture_image_size) == NULL) {
       fprintf (stderr, "design validation error: theme-defined image size '%s' not found\n", theme->picture_image_size);
       return FALSE;
     }
+    if (theme->album_thumb_size) {
+      image_size = lookup_image_size_for_name (setup, theme->album_thumb_size);
+      if (image_size == NULL) {
+        fprintf (stderr, "design validation error: referenced thumbnail image size '%s' not found\n", theme->album_thumb_size);
+        return FALSE;
+      }
+      if (! image_size->is_thumbnail) {
+        fprintf (stderr, "design validation error: referenced thumbnail image size '%s' is not of type \"thumbnail\"\n", theme->album_thumb_size);
+        return FALSE;
+      }
+    }
+    if (theme->index_thumb_size) {
+      image_size = lookup_image_size_for_name (setup, theme->index_thumb_size);
+      if (image_size == NULL) {
+        fprintf (stderr, "design validation error: referenced thumbnail image size '%s' not found\n", theme->index_thumb_size);
+        return FALSE;
+      }
+      if (! image_size->is_thumbnail) {
+        fprintf (stderr, "design validation error: referenced thumbnail image size '%s' is not of type \"thumbnail\"\n", theme->index_thumb_size);
+        return FALSE;
+      }
+    }
   }
 
   return TRUE;
@@ -525,9 +577,11 @@ free_design_theme_data (TGalleryDesignTheme *theme)
   if (theme) {
     g_free (theme->index_template);
     g_free (theme->index_filename);
+    g_free (theme->index_thumb_size);
     g_free (theme->album_template);
     g_free (theme->album_filename);
     g_free (theme->album_image_size);
+    g_free (theme->album_thumb_size);
     g_free (theme->album_protected_thumbnail);
     g_free (theme->picture_template);
     g_free (theme->picture_filename);
diff --git a/src/setup.h b/src/setup.h
index 9e8f9dd..64351f3 100644
--- a/src/setup.h
+++ b/src/setup.h
@@ -35,12 +35,6 @@ G_BEGIN_DECLS
 /*  forward declaration  */
 typedef struct TGalleryDesign TGalleryDesign;
 
-typedef enum {
-  THUMBNAIL_SQUARE_TYPE_NONE,
-  THUMBNAIL_SQUARE_TYPE_SIMPLE
-} ThumbnailSquareType;
-
-
 /*  Global gallery setup  */
 typedef struct {
   gboolean verbose;
@@ -63,7 +57,6 @@ typedef struct {
   gboolean strip_xmp;
   gboolean write_supplied_exif;
   gboolean nofullsize;
-  ThumbnailSquareType squared_thumbnail_type;
   gboolean autorotate;
 
   /*  meta section  */
@@ -96,6 +89,7 @@ typedef struct {
 
 typedef struct {
   gchar *name;
+  gboolean is_thumbnail;
   int landscape_width;
   int landscape_height;
   int portrait_width;
@@ -103,15 +97,18 @@ typedef struct {
   int square_size;
   int quality;
   gboolean no_resize;
+  gboolean squared_thumb;
 } TImageSize;
 
 typedef struct {
   gboolean enabled;
   gchar *index_template;
   gchar *index_filename;
+  gchar *index_thumb_size;
   gchar *album_template;
   gchar *album_filename;
   gchar *album_image_size;
+  gchar *album_thumb_size;
   gchar *album_protected_thumbnail;
   gchar *picture_template;
   gchar *picture_filename;
@@ -153,9 +150,14 @@ TGalleryDesign * parse_design_setup_xml (const gchar *filename);
 TGalleryDesign * makeup_legacy_design (const gchar *filename);
 
 /*
+ *   lookup_image_size_for_name: looks up an image size record for given image size name
+ */
+TImageSize * lookup_image_size_for_name (TGallerySetup *setup, const gchar *name);
+
+/*
  *   validate_design_setup: validate design.xml file setup
  */
-gboolean validate_design_setup (TGalleryDesign *design);
+gboolean validate_design_setup (TGallerySetup *setup);
 
 /*
  *   free_setup_data: free allocated setup data
diff --git a/templates/default.xml b/templates/default.xml
index 318531c..9197519 100644
--- a/templates/default.xml
+++ b/templates/default.xml
@@ -45,7 +45,10 @@
     <!-- Thumbnail section is mandatory. -->
     <!-- Corresponds with optional <item thumbnail> tag in album source file.
          Note that thumbnail images are always resized even for custom supplied files.  -->
-    <size name="thumbnail">
+    <!-- The "type" attribute has to be set to "thumbnail" to be treated as such.
+         An optional "style" attribute set to "squared" indicates the need of squared
+         thumbnails as opposed to original aspect ratio. -->
+    <size name="thumbnail" type="thumbnail" style="normal">
       <landscape w="180" h="120" />
       <portrait w="120" h="180" />
       <square size="180" />
@@ -74,6 +77,8 @@
     <index>
       <template>template_index.html</template>
       <target_filename>index.html</target_filename>
+      <!-- specify thumbnail image size to be used here. -->
+      <thumbnail_size>thumbnail</thumbnail_size>
     </index>
 
     <!-- This is mandatory. -->
@@ -82,6 +87,8 @@
       <target_filename>index.html</target_filename>
       <!--  which picture size to use for XXX tags (TODO)  -->
       <picture_size>preview</picture_size>
+      <!--  thumbnail_size is optional when thumbnails are not used on album pages  -->
+      <thumbnail_size>thumbnail</thumbnail_size>
       <!--  In case of a protected album, show special thumbnail (must be included
             in supplemental_files). Comment out to use real thumbnail  -->
       <protected_thumbnail>emblems-readonly_120.png</protected_thumbnail>