--- control-center-2.7.0~/capplets/background/gnome-wp-info.c	2004-07-06 23:13:16.000000000 +0100
+++ control-center-2.7.0/capplets/background/gnome-wp-info.c	2004-08-16 17:42:07.365001528 +0100
@@ -22,6 +22,36 @@
 #include <gnome.h>
 #include "gnome-wp-info.h"
 
+static void _invalidate_thumb (const gchar * uri, const gchar * thumburi) {
+  GnomeVFSFileInfo * info;
+  GnomeVFSResult result;
+  time_t mtime, thumb_mtime;
+
+  info = gnome_vfs_file_info_new ();
+  result = gnome_vfs_get_file_info (gnome_vfs_escape_path_string (uri), info,
+				    GNOME_VFS_FILE_INFO_DEFAULT);
+  if (info != NULL && result == GNOME_VFS_OK) {
+    mtime = info->mtime;
+  } else {
+    mtime = 0;
+  }
+
+  result = gnome_vfs_get_file_info (gnome_vfs_escape_path_string (thumburi), info,
+				    GNOME_VFS_FILE_INFO_DEFAULT);
+  if (info != NULL && result == GNOME_VFS_OK) {
+    thumb_mtime = info->mtime;
+  } else {
+    thumb_mtime = 0;
+  }
+
+  gnome_vfs_file_info_unref (info);
+
+
+  if (!mtime || !thumb_mtime || mtime > thumb_mtime) {
+    gnome_vfs_unlink (thumburi);
+  }
+}
+
 GnomeWPInfo * gnome_wp_info_new (const gchar * uri,
 				 GnomeThumbnailFactory * thumbs) {
   GnomeWPInfo * new;
@@ -66,6 +96,7 @@ GnomeWPInfo * gnome_wp_info_new (const g
 				   gnome_thumbnail_md5 (gnome_vfs_escape_path_string (uri)),
 				   ".png",
 				   NULL);
+      _invalidate_thumb(uri, new->thumburi);
     }
     new->name = g_strdup (info->name);
     new->mime_type = g_strdup (info->mime_type);
