I am annoyed

So, I've been trying since the day after St. Patrick's Day to change my background, but I can't. It used to be so easy, but now for some reason it's not working. I try it a few times every week. Ugh. Sorry for the St. Patty's background. I'm either very untech savvy for leaving it on, or I'm very prepared for next year. Let's pretend it's the latter. Any suggestions?