Stop being poor, save up and buy a 512 ground texture. Its not worth the time the devs would have to spend to readjust the ground texture to do that. Like Link said, just add white space. If you're seriously not willing to add a bit of white space, then I honestly don't think you're that worried about having your image like you want.

Keep in mind the devs current time is being devoted to things that will make the game better by larger amounts. Not backtracking to tamper with things like ingame items and textures.