I often upload large batches of photos to a category and post a subset of the pictures in a thread. I then tell people to visit the category to see the rest of the pictures and provide the link to the category. If more pictures are added to the gallery, newer pictures will show up instead when the linked is clicked from the forum.
I would like to have the option to tag the pictures when uploading. When posting a link to the gallery, the tag could be included in the url and only those pictures would show up.
For example, if I had batch of pictures from the 2007 Dream Cruise, I would upload the pictures with a tag like dreamCruise07. When linking to the forum, the url would be something like
http://gallery.com/browseimages.php?...=dreamCruise07 . This url would limit pictures from category 99 with the dreamCruise07 tag. If no category was listed, then all picture with the tag from the whole category would be shown.