how would I manage pixel-by-pixel rendering in WPF (like, say, for a raytracer)? My initial guess was to create a BitmapImage, modify the buffer, and display that in an Imag
I highly recommend against the previous two suggestions. The WriteableBitmap class provides what you need assuming you are using 3.5 SP1. Before SP1 there's no really good answer to this question in WPF unless you resort to some serious trickery.