It is hard not to think that a great deal of time an money would have been saved by removing those "Parts of our technology are built using OS X’s graphics frameworks, which offer high quality output and excellent performance."
I imagine more advanced things like face recognition and such are not so simple, but from my experience writing a raw converter, a lot of image processing is far simpler than you'd expect.
A lot of the complexity comes down to not just doing the operation, but doing it correctly and quickly. ImageMagick does multiple passes, for instance; this is sub-optimal for both quality and speed.
