Yea, you did. But not "fully".
How to Take a Screen Shot:
Press PrntScrn on your keyboard, which is right of F12. After that, open up any imaging software (such as MS-Paint) & click Paste (Ctrl+V). Then save the image and upload it using any host (A few recommended ones are below).
How to take a in-game automatic screenshot
When you are in game, playing. Press F5. a automatic BMP image file will be created in the mod folder you are playing, so in this case "steam/steamapps/username/game/ESF"
Where to Upload the Pictures:
Image Shack
PhotoBucket
Ripway
ImageShack is recommended as it require no signing up.
Posting the Picture:
To get it to appear on the page, you have to use the image tags like this:
[.img]http://www.yourwebsite.com/image.jpg[./img]
Remember, remove the . in the img tags above. So you only see
, if i removed those dots above. The forum would make an image out of it.