1. Take the screenshot using the PrntScrn key on your keyboard
2. Open MSPaint, GIMP, PhotoShop, or some other graphic design application.
3. Past the screenshot with Ctrl+v (paste)
4. Save the file (.jpeg is good)
5. Go to a site like
http://imageshack.us/ and upload the pic
6. When it's done, copy the URL of the image and paste it in here as a link, or put the image itself in a post by using
[img width=640 height=480]http://.../url.jpg[/img]
If you took an in-game screenshot, it will be in paintball2/pball/scrnshot, so just do steps 5 and 6 with it.