See it in action and get started using it at http://openseadragon.github.io/.
See the GitHub releases page.
If you want to use OpenSeadragon in your own projects, you can find the latest stable build, API documentation, and example code at http://openseadragon.github.io/. If you want to modify OpenSeadragon and/or contribute to its development, read the contributing guide for instructions.
OpenSeadragon is released under the New BSD license. For details, see the LICENSE.txt file.