Click on the "Reply" instead of using the normal reply box at the bottom. It takes you into an advanced screen. In the lower left hand corner there is a "File" and a link "Click here to upload!". You can then add a shot from your computer. If you have the shot that you want to upload on another site you can use the Image box below the emoticons to put the link in there.
This site is pretty much like others when it comes to uploading pix.