Step 1 - make sure the image you want to use is on the web somewhere. Many people use webshots, others have a website with their images on it.

Step 2 - figure out the address of the photo - it should look something like this:
http:// DogoftheDay.com/archive/2001/JuneImages/ 19s.jpg but without the spaces I put in. Notice it ends with ".jpg" not ".html" - that would be a page, not an image.

Step 3 - type [img] paste your image link here - no spaces!!! then type [/img]

So this: without the space in the middle ends up being this: