StainedGlass,
A third party application to change the uniforms would be nice. All that would be required is for everyone that is contributing to make their templates available. Would complicate the application though since the progam would have to know which template to use for each picture (probably would have to have the user select the proper template).
Just by using PhotoShop, I was able to change uniforms in just a short bit of time. Just copied the photo in as a new background, deleted the background portion of the photo (helps that it is almost a solid color) and made new uniforms visible.
