The same entries can show up at least twice in the beauty contest
judging, even after you have rated them. I asked about it in the
help thread, and someone confirmed that, yes, I was probably seeing
the exact same entry when I saw the same image again about 5 - 10
minutes after I rated that entry. He thinks it may be a bug so I'm
starting a thread about it in the bug forums.
I tested 522 images if they're the same and I didn't find a single
duplicate. I tested this on image name and the actual image data. I
don't think you'd even rememeber how an image looks exactly after 5
minutes and 500 images. It's probably just some images that look
really similar.
I wasn't the only one to notice it. Someone else said that they
found the exact same image with the same id as another image with
going through the judging.