I've cut and pasted this from an older thread.
First you need to find some web space to upload the picture to, there are a number of free services available (photobucket is one I know of but I know there are others). Once it's uploaded you just need to put the URL inside the image tags and you're off and running.
the image tags use the square brackets [ ], I'll use parenthesis so you can see the tag
(IMG)http://i448.photobucket.com/albums/qq209/Soulyss/P39snapshot.jpg(/IMG).
If you replace the () with [] brackets you'd see this.

To get the screen shot in the first place you can go into the film viewer and set up the shot you want. On the right side you'll see a button that says "full screen view" click that and once the screen loads hit the Print Screen button on the keyboard. This will copy the screen capture to the windows clipboard. Now you just need to open up a graphics editor and paste it in. Re-size to your liking and upload it to the hosting webspace.