>>7705776Okay so this might be a bit hard to explain over 4chan but I'll try. I ended up being able to do it in GIMP like this:
1. Expand the canvas to a some relatively massive size without expanding the actual image (e.g. it could be automatically filled with white in the places outside the pape)
2. Copy and paste some arbitrarily large portion of the horizontal end of the image, and place it on the OTHER end of the image.
3. Place the pasted floating section at exactly the right place where it's seamless (i.e. the pasted copy is somewhat on top of the original image)
4. Select the now-larger-in-that-dimension image (e.g. if it were a square, you'd be selecting a rectangle now)
5. Crop to selection
6. Repeat steps 1-5 for the other dimension if it tiled neither vertically nor horizontally.
There might be a much quicker way to do it since I just pulled the entire routine out of thin air lol
