I can't delete photos from a gallery

I've been trying to update my poster on my short film page and delete the old one, but it doesn't let me delete any photos. I've looked it up like a million times and they always say that there is a delete button but I've literally never seen one before. What do I do to get rid of photos and posters in the gallery easiest? This also could be an IMDb Pro problem, which I do have, so please let me know.