I use Jing to do just this. It works on Windows and Mac and next to Screenshots also allows to capture up to 5 Minutes of Screencast at a time. Then I have the

I use Jing to do just this. It works on Windows and Mac and next to Screenshots also allows to capture up to 5 Minutes of Screencast at a time. Then I have the save location set to the Public Dropbox folder and the link is automatically put into my clipboard.