Cropper is an open source screen capture tool written in C# .NET that allows users to mark a region in their desktop and take a screen capture and save it to any image type format.
Its simple, light weight and its free.
Cropper was support for plug-ins (extensions, add-ons what ever you want to call it). You can create your own extension in .NET to enhance the functionality of cropper.
I used it for my development for to take a snapshot of an error for example and then automatically uploading the capture image to the issue management application such as “Mantis”.
Compare to SnagIt, cropper does not have all the features in SnagIt out of the box but there are several extensions for cropper our there that can provide a similar functionality. You’ll find the plug-ins download sites here.