Although the ruling dealt with open source programs, it did specify that copyright holders have the right to control the modification and distribution of copyrighted material even if there was no direct compensation.
It says basically that if provisions are made regarding the material that are not lived up to, it is an infringement of copyright rather than breach of contract. This allows the copyright holder to prevent the infringer from using the material.
One could make the argument that if you allow a customer to distribute your image, they have to include your copyright notice on it if that is a condition of the license.
