When you click "REPLY" on posts with images, you can actually SEE things in brackets. Looks like junk, but they're TAGS. You can do this yourself without a full reply.
For instance, when I quote someone, I use tags with "quote" and "/quote" within brackets:
Code:
[quote]Todd is semi-awesome.[/quote]
Resulting in....
Quote:Todd is semi-awesome
That will put "Todd is semi-awesome" in quotes.
Now, for images, you put "img" and "/img" in brackets, surrounding the image URL you want to post:
Code:
[img]http://wmubroncos.com/images/logo_large.png[/img]
Resulting in...
... as I found that WMU logo from:
http://wmubroncos.com/images/logo_large.png, by bringing up a pop-up menu over a graphic in my browser and selecting "Copy Image Location".
See how that works? It's easier than clicking on the right icons in a full reply! IMO, it's easier just to type it out. You copy-n-paste an image URL from somewhere and put it in-between "img" and "/img" tags made of brackets, and viola.
Try it out, it's easy. :)