In recent days I have developed Document Management system. In this application user can manage various type documents including txt, rtf pdf, bmp, tiff and many others file formet documents, so there were need to edit document with rotating, cropping, color image processing functionalities, converting document in various file formats and many other functionality like image loading in application, compressing, image display, scaning image etc.
I need a powerful tool, then I used leadtool document imaging developer toolkit, it is very easy for implementing in windows application. This toolkit is also available as WCF services and WF activities. In last I have implemented all these functionalities in application successfully.
If you need to like this you can also try :
http://www.leadtools.com/sdk/document-imaging.htm