Once you have the pics resized and posted to an image hosting site like Flicker, you can insert them into a post. While creating a post or a reply, in the message menu you'll see some icons.
One looks like a globe with a link symbol, the one to the right of that is a link symbol with a red X through it, and the one to the right of that sort of looks like a yellow post card. The post card one is the icon for posting the url to your image. Just click it and insert the url into the proper field and your image will be inserted into your post.