In your rejection email, there is a link provided at the bottom of the rejection message where you can find out what pictures were rejected.
It takes you to the appeal section of the page and lists your recent rejections or your last 50 rejections.
Link looks something like that.
(I also changed a few letters so it wont show any picts)
Follow @kimbo_snaps on Instagram or bokimon- on Flickr to see more pics of me and my travels.