I'd like to create a tiled image (is that the right term? A small image that can repeat seamlessly, I mean) using a very subtle texture of some kind. I had a go at making this in an image editor, but I failed to produce a nice result because I'm a novice at anything to do with graphics or image editing. So is there some kind of web-based image/graphics editor that could let me do this easily? I've heard that such sites exist, but I've never used them before.