Zoom.it is Microsoft’s Live Labs online tool which makes sharing and viewing of high-resolution images easy. It converts any online image into Deep Zoom Image format and then making it easier for you to explore images which are of very high-resolution i.e. image which are pretty big and does not fit in your screen
You can use the plus,minus icons to zoom in and out. And keep your left click pressed to drag the image.Once you give your online image link it creates a script which can be embedded in any webpage for your viewers. Zoom.it runs uses the Windows Azure and Silverlight. There is also an API available (api.zoom.it.)which you can use.