To make a screenshot, press "PrintScreen" next to F12. Open Paint, paste the picture and save it as png or jpg. Open a new tab in your web browser and type http://imageshack.us
and upload your picture. After you are done you will get a list of links. Copy the second
one that says "Thumbnail for forums (1)" next to it and post it.
Oldest and cleanest:
Current, Made the wallpaper myself with media player and Irfanview: