I use a little utility called GrabBox that does something similar:<p><a href="http://grabbox.devsoft.no/" rel="nofollow">http://grabbox.devsoft.no/</a><p>When you take a screenshot using any of the built-in tools, you'll see a Growl bubble asking whether you'd like to share the photo. Another one will ask if you'd like to give it a custom name. When you click, the screenshot is copied to your Dropbox/Public/Screenshots, and the public URL is copied to your clipboard. It's pretty slick.