For future reference, you really shouldn't flag the post for deletion while it's pending moderator approval. While the image is pending it'll automatically be deleted 3 days after being uploaded if it isn't approved.

This image seems to have had the bottom cropped off, which perhaps was the reason the similar search didn't work.

The user who uploaded is a Contributor, though, so I don't think it was pending moderator approval.

Odd, I definitely missed that. I Thought I had checked that to make sure he wasn't contributor status. *shrug* my mistake.