Addition to #816

To start with, I haven't used ruby that much before so I'm still a bit of a noob. So sorry about that.
Never the less it looks like it's doing what it's supposed to do.

1. Added extension check for images. Will fail if not .png (the default extension we seem to be using)
2. Pasted the #816 code and my new one to the providers section.
3. A bit of formatting. Hope no one is against that. (Did it automatically #BlameCarlgo11)
4. updated the images that didn't qualify for the new checks.