maybe the pattern on the swimsuit :S ... i dunno
I agree it seems convincing when all the other sites didn't find a problem however different sites have different standards as well.
I submitted some christmas ornaments of little troll figures once. All the sites accepted them, while canstock was worried about copyright on the figures and didn't accept them.
I submitted some ginger bread houses, that were decorated in TONS of m&m

that was a silly thing to do, as i had to go and erase all the little m's on the candies. Anyhow i did that, submitted them, and they were accepted to all the places...... except istock.. which found some m's that i missed

not to stand up for istock however, i am quite often frustrated with the reviews... sometimes just try to forget about it, and other times try and fix it, and some times just get frustrated.