Where to get In game champion pictures

In game you are able to see your champion with a circle around it. It changes depending which skin you have. I was wondering if there was some location I could get all those pictures. Want to build an app but without the art it would be much less exciting. I found some sites like this one:

http://leagueoflegends.wikia.com/wiki/Category:Champion_squares

But this does not have the ones for each skin. Anyone know where I could find all these pictures?