A small plugin that adds ability to easily add zoomable images to posts. The frontend functionality is handled by Magnify JS.
To use, add the following shortcode to your post:
[magnify id="123"][/magnify]
The id attribute is the ID of the image attachment.
The plugin also adds the shortcode to the Media Library screen as a inconvenience. Once you've selected an image, the shortcode can be found in the sidebar.