带有可拖动的第二张图像的背景图像（可能是图层）

I need to be able to take a background image and float a second draggable image (should be scalable, but with fixed proportions) Also the code should be able to 'flatten' the image for photo sharing. Oh, also the floating image should have a dropped shadow to give the illusion of depth. Thanks! Is this possible with jQuery, ajax, Yui or Dojo(other?)? Or am I barking up the wrong proverbial code trunk.I need to be able to take a background image an