SnipDock
Snip screenshots and dock them so you can refer to them while working.
... the space used by SnipDock, even if they are maximized.
4. You can zoom in or zoom out of the image by scrolling your mouse on the image.
5. Any image snipped will be automatically stored in your Pictures folder. So you could also use SnipDock just to snip screen and store the images.
Shoot me an email at rahulhuilgol@gmail.com if you have any queries/suggestions.
Source on github http://rahul003.github.io/snip-dock