Add a base class for filtering images, that can be extended by the user to implement actual filters.
Later, perhaps, distribute some filters mfImage.
Typical filters would be: Level + gamma filter, brighness, sharpening, blur, gaussian blur, unsharpen mask, invert, Hue+Saturation, ...
Note that all those filters should be implemented for:
RGB, CMYK, GRAY, LAB
in 8,16,32 bit depth! Or perhaps need a "canFilter" that returns false for unsupported image types.