Let users crop. CropImage.NET is a drop in replacement for the old ASP.NET WebCropImage control. No more memory leaks, much better Javascript, and a consistent API that is 95% compatible with WebCropImage (We broke compatibility on a number of features by actually implementing them).
Designed for .NET 2 through .NET 4, rest assured it will work with your project.
If you want more or less than CropImage.NET, StudioJS is what you need. It's a collection of jQuery plugins that can provide anything from CropImage.NET to a full-fledged image studio.
The compact ImageResizing.NET library is the safe way to crop, resize, and process your images. It's designed for server-side use and has a simple API. It's what CropImage.NET uses.