They were probably removed from the hosting site.
Artists will not keep pieces on their accounts forever, they have to be removed to make space for new pieces, you'll be lucky if they're even on her computer anymore.
This is why you always save them to your own computer.
If the site has a limited usage per month of how much you can upload, they may have simply gone ver that which means the pictures will be back in a month. But That happens with Photobucket, I'm not to sure on the site they use.