Would put a picture in but can't figure out how to do it.
You need a piccy hosting site (flickr) that provides a direct link to the piccy, then copy that URL and past it onto the pop-up box that can be activated by the small 'camera' icon button above where you type your message.
To use flickr do the following:
You need to view the image you want in flickr, then right click to get the options for the various sizes, and select the one you want...
Then right click that image and select 'View Image' - that will then directly open the image on its own - no 'flickr' stuff around this displayed image.
That URL is then what you place into the 'BB Code for Picture Insertion' option (the button that looks like a small camera).