Ok it might be different where you live but what I learned in a course about creating websites was that it is okay to use other people's work as long as you don't take credit for it and it is clearly recognizable who the copyright holder really is (like when you write a essay in college and add a "source sheet" appendix where you list all the books you used). This same problem basically applies every time you quote a newspaper article or something and it is pretty common rule that you are allowed to do that as long as you tell the source. I'd say: As long as you don't take credit for the texture and mention where it came from all that could possibly happen to you is that you will be asked to remove it.