I've actually seen weird things like remnants of the old image in people's images before. It will appear normal on the site, but when I download it and open up the image, it has weird things throughout it. It doesn't look like the person simply forgot to edit those parts out, because it's so clear that they are there that no one could miss it. It looks like an actual weird glitch. I don't know the cause of it, but maybe that's what's going on here.