To post on someones message board you will need an HTML code. If you like a certain picture, you can right click and save it to your computer then upload it via a Photo hosting site. The most common site that people use is Photobucket.com. Its free to sign up. If you see pictures on other comment sites, they usually have the html codes on their sites as well to use where you don't have to do any uploading. There is tons of sites out there. I always search as myspace comments and get all the sites. In photobucket, you will find the html code here...click on and copy it.
then past it to the message board
and post. Voila!