Played around with Paint.Net a little, and ended up trying to make something related to Minecraft. Within 20 minutes I pretty much only came up with this. I think it's pretty good for a first try. It's a diamond sword, and the D in the handle represents my username.
(http://i.imgur.com/UjxF6y4.jpg)
Got another image made up. A cave with the sword I made along with a torch.
(http://oi46.tinypic.com/11uavl3.jpg)