I knew it was a .jpg file. The problem I'm having is were to edit to. I tried deleting everything before the JFIF, as well as leaving just one . before the JFIF, but no matter what I do I get an error "Couldn't open the file. It may be corrupt or a file format that Preview doesn't recognize."

It turns out what you have to do is actually delete up to and including where it says "data" and nothing else.

In the screenshots, it shows text like "data.PNG" and they tell you to delete everything before the ".PNG" part.

Well the same thing applies to if it instead says JFIF, it'll look like "data………..JFIF" or something, just delete up to and including the "data" part so then the start of your file would look like "……..JFIF" (not sure how many dots there are exactly, just all the dots after data, leave them).

That works for me as of iTunes 10.