Hold your mouse pointer over Mickey's cat's testicles (five posts above this one) and you'll see he's using a 'Photobucket' server. The URL of the image will show up. The "
http://i154.photobucket.com" part of the URL is the name of the server and everything to the right of that (".../albums/s248/... etc.) is where on the server the image is located. The URL ends with the name of the image file and its file type (.../IMGPO269.jpg)
What you need to do is get your image (usually a jpeg file) on to a 'Photobucket' server by creating an account with them, like Bill suggests. Upload the photo then view that image in your web browser. The URL of the image will be in your browser's 'Address' bar. Paste that URL in between the [img]and[/img] tags in one of these posts and it should show up.
I hope this makes sense!