Image Processing on Raspberry Pi
Python has a lot of import libraries for image processing, and they are running on platforms that support Linux, such as Raspberry Pi.

Pi runs with ARM based processors, and every limitation of that CPU (especially on SIMD floating point ops) is also a limitation for image processing. 

Pi also comes with a dedicated hardware GPU which can be used to accelerate certain image processing (computer graphics) functionality (in addition to its image/video encode and decode functionality) 

Pi also comes with built in camera interface that would enable raw processing of camera data, using available Python libraries.