Make --cache-thumbnails adhere more to the standard

ChangeLog

@@ -3,6 +3,7 @@ git HEAD
     * Patch by aaptel: Support numpad keys for actions
     * Fix blur mode (Ctrl + left mouse key)
     * Center images in index/thumbnail mode relative to the text below them
+    * Various thumbnail caching improvements, better standard implementation
 
 Thu May  6 08:34:39 CEST 2010  Daniel Friesel <derf@chaosdorf.de>
 

man/feh.1

@@ -134,9 +134,9 @@ Create borderless windows.
 Use builtin HTTP client to grab remote files instead of
 .Xr wget 1 .
 .It Cm --cache-thumbnails
-Enable thumbnail caching in
-.Pa ~/.thumbnails
-(rather experimental).
+Enable (experimental) thumbnail caching in
+.Pa ~/.thumbnails .
+Only works with thumbnails <= 128x128 pixels.
 .It Cm --caption-path Ar path
 Path to directory containing image captions.  This turns on caption viewing,
 and if captions are found in

src/options.c

@@ -797,6 +797,7 @@ static void check_options(void)
 		free(opt.thumb_title);
 		opt.thumb_title = NULL;
 	}
+
 	D_RETURN_(4);
 }
 
@@ -960,7 +961,8 @@ void show_usage(void)
 "                           OPTIONS\n"
 " -t, --thumbnails          As --index, but clicking an image will open it in\n"
 "                           a new viewing window\n"
-"     --cache-thumbnails    Enable thumbnail caching\n"
+"     --cache-thumbnails    Enable thumbnail caching for thumbnail mode.\n"
+"                           Only works with thumbnails <= 128x128 pixels\n"
 " -~, --thumb-title STRING  Set window title for images opened from thumbnail mode.\n"
 "                           Supports format specifiers, see there.\n"
 " -I, --fullindex           Same as index mode, but below each thumbnail you\n"

src/thumbnail.c

@@ -717,7 +717,7 @@ int feh_thumbnail_get_thumbnail(Imlib_Image * image, feh_file * file)
 		if (!status)
 			status = feh_thumbnail_generate(image, file, thumb_file, uri);
 
-		printf("uri is %s, thumb_file is %s\n", uri, thumb_file);
+		D(1, ("uri is %s, thumb_file is %s\n", uri, thumb_file));
 		free(uri);
 		free(thumb_file);
 	} else