SXC.HU stocks are now forbidden because they have change the rules of their distribution and copyrights system.
``Photo manipulation does not grant you copyrights to the image therefore you cannot use sxc.hu images in the described manner. You cannot create derivative works with the use of sxc.hu images. Furthermore, you need the original artist's permission to use their work in a derivative composition.´´ fav.me/d5wzrlo
Unless you get the permission from the owner. This is their new rule.
Official blog by Aeirmid