down the probability distribution into a product over every single feature so for an image you estimate the probability of each pixel given all of the pixels that came before it hmm there's tricks where if you want to measure the density function you can actually calculate the density for all these pixels more or less in parallel generating the image still tends to require you to go one pixel at a time and that can be very slow but there again tricks for doing this in a hierarchical pattern where you can keep the runtime under control or the