You can encode your video source to a sequence of images (PNG, JPG, DPX) with MWriter (MFWriter) object using 'image2' encoding format.
The overall configuration looks like
format='image2' video::codec='dpx' audio::codec='null'
Supported extensions that you can use as video::codec value:
With WriterNameSet (or WriterSet) method, you set the configuration and a path to the resulting file. For image sequences, the result is a folder with a file name which content is of files with names like [file_name][index].[extensition], e.g. "test_sequence_0000070.bmp".