Screen Draw is a firefox add-on to draw on any page without needing to screen shot it and then edit it later Now do it all inside of firefox with Screen Draw . Screen Draw lets you draw or type text over the top of any page in any colour or size and then save it to png or jpeg. To use it go to toolbar and find the Screen Draw icon. Once you click the icon you will get the Screen Draw toolbar which lets you select brush, text, colour, new, eraser and save.
Download Screen Draw