A "bad" image is a photo that is structurally unsound (it may display as a thumbnail, but has an internal error that does not allow it to print), or it is far too small to print -- for instance, a 100 x 150 pixel image would not print as a wallet.
When a bad image is ordered and detected, it is removed from the order and deleted from the system. dotPhoto deletes bad images because it is our experience that customers continue to try to order the bad image, which is very frustrating because a bad image will never print.
If you like, we can tell you the file names of the bad images. This may enable you fix the images or to combine them in a collage so that you have a printable image before uploading them again.