Why AI textures show seams
Image models paint a single picture, not a tile. Even when asked for a seamless texture the right edge rarely continues the left edge, and the picture is often lit like a photo, brighter in the middle and darker toward a corner. Repeat it across a floor and you see a grid of hard lines and a checker of light and dark patches.
How the fix works
Even out the lighting. The tool measures the slow change in brightness across the texture and lifts the dark parts and lowers the bright parts, so each copy looks the same next to its neighbour. Cut a tile. It lays the right side of the texture over the left side, finds the path through the overlap where the two differ the least, and switches from one to the other along that path. The same is done for the top and bottom. Because the cut follows the texture, stones, planks and blades of grass stay whole instead of turning into a ghostly cross-fade. The report shows how visible the edge is compared with any other line of pixels, so 1.0× means you cannot tell where the tile ends.
Normal maps
With Pro you also get a normal map made from the brightness of the tile. It wraps at the edges too, so lighting has no seam either. Choose OpenGL for Godot and Unity, DirectX for Unreal.
Is my texture uploaded?
No. Everything happens in your browser.