Image cropper was added into Umbraco v7.1
This image cropper package has been superseeded by the Image Cropper which is included in Umbraco v7.1 - so upgrade your installation instead of installing this package :-)
Full documentation on the v7.1 cropper can be found here
Joost van den Berg who created the original v7 Angluar JS image cropper upon which this package is based.
Warren Buckley who created the UmbracoExtensionMethods from which the ImageGen extension method is derived.
Nathanael Jones who created both Slimmage and SlimResponse which are included in the package. Both project are MIT/Apache dual licensed by Imazen.