C# wrapper for a super fast super quality image codec

The required dll is to be used in a silverlight "inbrowser" application that will take snap shots from a web camera and stream them to a server. the freelancer is required to develop a dll to be used in C# language that will take a bmp image and output a high quality low size image . the size of the output image should not exceed ~3k bytes. you can use any codec you like but we would prefer if you can WebP codec by Google as it seems to have a good future and good support. the requirements can be further discussed and changed to best suite the solution we seek.