This returns info of an image if it exists or raises an exception if it doesn't!

This is related to the code on the frontend imagehelper, there is a comment about it, but I can also add here.
This verification should be done on the frontend to see if the url returned actually exists using this:

http://stackoverflow.com/questions/92720/jquery-javascript-to-replace-broken-images

but right now is just faster to do this!