In light of a recent request by an artist to remove all his pictures from the site and Twitter and anywhere else (there is nowhere else), I have made a change to the site’s Submissions Guidelines. I added the sentences which are bolded.

Please note:

Any disputes over images will result in your image(s) being removed immediately from the website and the gallery. You may, at any time, ask us to remove, for any reason, images from website or the gallery. You will still be liable for gallery print costs. You will have to remove your own pictures from your page. We will remove any posts from the main timeline of posts. Since they will no longer exist, we will not bother to delete tweets with your images on Twitter, since the Twitter posts no longer link to anything on the website. If your image has been chosen for inclusion in a book, you have up until the time we create the book to ask it be removed.
If we have created and submitted the book, too late! Frankly, we can’t see why anyone would want to do this, but artists can get funny sometimes.