Unfortunately I wasn’t able to get the hang of this tool. I tried a couple of images, some of which were already seamless textures, but the result did not look like a seamless texture.
The texture size selectors didn’t seem to be working. And I noticed that they only go up to 1000, which seems arbitrary. Why not 1024px? Or better yet, no limit at all?
Let me know when you’ve worked out these issues and I’d be happy to try it out again and update my score accordingly.