You can add comments to photos like this:
try adding this to your photo-album/photo.tcl:
set comment_link [general_comments_create_link $photo_id "[ad_conn package_url]photo?photo_id=$photo_id"]
set comments [general_comments_get_comments -print_content_p 1 -print_attachments_p 1 \
$photo_id "[ad_conn package_url]photo?photo_id=$photo_id"]
then add this to your photo.adp:
@comment_link@
Hope this helps. I think you can add comments to any content item. Im not that sure about it though. But I made it work for photo album