If you already have screenshots of your model/renders:
1.) Upload the pictures you want to show on a website/host. You can find plenty of free hosts on google, example: geocities.com
2.) Link the URL of that picture, example: ¬
www.geocities.com/~liuxaz/mypic.jpg¬ inside a [IMG.] * [/IMG.] tag: replacing the * with your URL and removing the .'s in the tags.
3.) Type in the full tag/bbcode in a fresh post, and your image will appear on your post.
*Moved* to help, since this thread isn't related to any model release/WIP directly.