I wasn't happy with URL's being disabled in BBcode in 1.4.21 because I was using one in an album description. I have a pretty good idea what the problem is but if I'm right it's only an issue when decoding user-submitted BBcode. I made a small modification so my album descriptions can still have URL's in them but users can't post URL's in their own descriptions or comments.
In include/functions.inc.php where the original line was commented out, I modified the function header for bb_decode:
function bb_decode($text, $decodelinks = false)
...then I put this block in place of the changed code:
if($decodelinks) {
$bbcode_tpl['url'] = '<span class="bblink"><a href="{URL}" rel="external">{DESCRIPTION}</a></span>';
} else {
$url_removed = '{URL}'; // put the image URL in the tooltip/mouse-over
$bbcode_tpl['url'] = '{DESCRIPTION}<img src="images/descending.gif" alt="" title="' . $url_removed . '" />';
}
...then changed the line in index.php that prepares the album description (line 536 in v1.4.24):
$alb_list[$alb_idx]['album_desc'] = bb_decode($alb_thumb['description'], true);
I hope this helps somebody else.
Patch for 1.4.2x (preserves BBCode img & url tags) (http://forum.coppermine-gallery.net/index.php/topic,58489.msg287677.html#msg287677)