Its pretty simple to do. If you need instructions here they are!
1. When your looking at your desktop press the "Print Screen" button.
2. Open any program used for editing photo's "Paint" is pretty standard and comes with all versions of windows.
3. Start a new blank picture (if not already opened to one) then hit Ctrl + v or just go to Edit > Paste.
4. Save your file and upload it somewhere like
www.photobucket.com or using the image upload on our forums.
4. Take the link and paste it here!
Here is mine:
I am NOT using a mac computer but it sure looks like I am with my customized programs, hehe.