What I do is simply click and drag the source URL up to where my tabs are in Firefox. This creates a new tab with the image, and avoids any external link blocking. Very convenient. I'm not sure if other browsers can do the same but I wouldn't see why not.
jxh2154's method is a foolproof way to get the links in FF. As for anyone using IE, simply click on "properties" for the image, and make sure you're getting the raw image url as opposed to the hyperlink code. Open up a new page/tab, and paste the url. If worst comes to worst, simply host it on PB or imageshack.