I have made images with multiple layers. They look really nice but when I try to apply them to another program, it comes up as an invalid image. Even microsoft won't let me use the image as a desktop backround. So please post whatever you know about this topic. There is nothing vulgar about the images. One website even said this,
"There is a problem with your upload. It could also be that we do not recognize your file format. Try converting to PNG."
I know it sounds stupid of me, but I don't know what PNG is or how to do that.