The proxy works! Only for a couple of image serving sites though (for security reasons, just imgur and postimg but I can add others per request).
So the idea is to add a prefix: "http://www.buzzerbeater.com/iproxy.ashx?" to the image URL (make sure to remove the second "http://" part), for example:
http://s24.postimg.org/wk44uudit/allstarbluecourt.png
becomes
http://www.buzzerbeater.com/iproxy.ashx?s24.postimg.org/wk44uudit/allstarbluecourt.png.