Over the last 18 months, I’ve been using my iMac as my main computer. I configured multiple Desktops (spaces) changed the screensaver, installed programs, games (Diablo 3 and Steam for Team Fortress 2). Basically making it my own, just like I do with Windows and Linux.
So one day I was looking at other features of Finder, and decided to change the window color from white to green for the Documents folder. You can do this by clicking the gear icon and Show View Options. After I goofed with the colors, I reset it back to white. then I noticed I can add a picture to the background. I copied over a jack-o-lanter picture I found last year and there was the small picture I copied. Then I decided to change the Arrange by from None to Name and clicked the Use as Defaults. I closed the window and didn’t think anything of it for a week.
When I came back a week later, I noticed some of my Finder windows had the jack-o-lanter as the wallpaper. I went through the process to remove the wallpaper, but noticed I could not change the wallpaper. It was stuck with the jack-o-lantern. After some searching on Google, I found a post by Pigstick on mac-forums.com which explained how undo what I did.
Change the Arrange by to None, then you can reset the background to any color or change the picture. Don’t forget to click the Use as Defaults button.