What I did only works with a photo that's already in the database, although you could also copy a photo that you'd posted in a thread. First, find the photo in the database that you want to add to your List entry and copy the BB code. Then go to your Lists Control Panel, click on the "edit" button for that entry, then scroll down to the "comment" section and paste the code in there. (Make sure to save your change). Very easy.