If you only want to include one link in your post, you can use the "Link Name & URL" area located below the reply window. You can also use the "Attach a File" area to browse to a file on your hard drive and upload it with your post.  There is a size limit though. Not sure what the limit is. I usually stick to less than 100,000 and it uploads ok.

If you want to include more than one link in your post, use the little blue "world" icon at the top of the reply window.  

If you want to include more than one picture in your post, you can do that too. You do however have to upload each one to a web hosting site, and then you can use the link to the picture in the little yellow "envelope" icon at the top of the reply window.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi