1. When you find an image you want on google, click it so you open it up in to it's own window and you
have some thing like
this. <-- Click
2. Now you see the address at the top of the page which says "http://www.brizweb.com/games/mathschallenge/balloons.gif"? Copy and paste that address in to your post.
3. Now so the computer recognizes that you're posting an image, you have to add [IMG*] at the begining of the address, and [/IMG*] to the end.
So it'll look like this: [IMG*]http://www.brizweb.com/games/mathschallenge/balloons.gif[/IMG*].
Hope that made sense.

Note: Just don't include the *'s. I only added them to break the code, so the computer doesn't try to post an image.