You need a paid subscription to remove photos. It doesn't really bother me if images stay on there since it's not my server.
Discussion
otherwise, I think the right section is here https://nostr.build/delete/
interesting.. it worked. Nostr build knows your npub when you upload an image. Which is what I thought, but I thought they would know only if you submitted the note. I didn't submit it and went to delete it and it asked me for my npub and I entered and it deleted it.
The nostr build developers are smart.