What I really trying to do is use one of my files (tree bark, for example) as a texture to apply to another image, just as the Patch tool copies texture from one part of an image to another. I know there's a Texture filter, but it's always "greyed out" so it's not a valid operation. What's the trick, and why is the Texture filter always grey? PS Help and the NAPP website have been of no use at all. Any advice greatly appreciated.