Resizing the image with good quality result is not simple task in CF, because Graphics InterpolationMode property is not supported. For breaking this limitation I developed a new library with the resampling engine made in C++ for ARM processors and a very simple C# wrapper for it. The engine implements a lot of buit-in filters with different speed and result quality.
The result of the resampling:
The original image dimensions 256x256 and resampled image 48x48
Note: When using this library you must distribute Resample.dll with your application.
Thanks to Carlo Pallini's for his idea of C++ resampling library.