I've done some searching, but I haven't found any software that supports .PSB on Linux. Perhaps there's a plugin for The GIMP that would work, but I was unable

I've done some searching, but I haven't found any software that supports .PSB on Linux. Perhaps there's a plugin for The GIMP that would work, but I was unable to find one, sorry... It's probably more trouble than it's worth, but you could install Wine and Photoshop on your Linux box, or find someone with a Windows machine and Photoshop who could convert the file to another format that you're able to use, like .PNG for example.