I noticed that when the link from description option is enabled https links are not recognised. I've updated my version with the follow small fix to make this work:
/* If the media description contains an url and the link option is enabled, use the media description as the linkurl */
if (($link == 'true') && ((substr($attachment->post_content,0,7) == 'http://') || (substr($attachment->post_content,0,8) == 'https://'))) $linkurl = $attachment->post_content;
Great plugin otherwise. Thanks a lot.