Javascript image editing

Hi,
I want a simple image editor functionality for my site. My requirement is like map annotations where I can draw squares and shapes on image and save the co-ordinates.

There are few scripts available for the purpose but none seems to be close to my requirement. Can you people recommend a good script for that?

Thanks in advance for the help.

Remember that what I am missing in current libraries is that when an image is being displayed, user is provided with toolbox to draw squares and shapes on image and save the co-ordinates so that when the image is reloaded the area are highlighted.