All you have to do is create an album and add your pictures to it. Then, View the picture and copy the "BB code" at the bottom that starts with . Paste that into your post and you're done.
If I have several pictures I want to put in a post, I'll copy the BB code test into a temporary text file, with a blank line in between. When you have all of the ones you want, copy & past the entire block into your post.