How do you get an image into a post/description?
Just, please use good etiquette about it and make the link to a site/page that you control (imageshack or photobucket, etc, are good for this if you don't have your own website that you can use to host images). Linking to an image on someone else's site is, on top of being impolite (hijacking someone else's bandwidth), it's also risky because you have no control over whether or not the image will remain on the site, or at the link you provide.
That's all addressed in the Help section on it, I believe, but the reminder never hurts.