A convolution model that makes images one pixel at a time, in order.
PixelCNN is like making pixel art with a hall monitor watching. Start top-left, and each new square may only peek at finished squares.
It can make small images and score how likely an image is. You meet it in early image-generation research.
Autoregressive Model
PixelCNN is an Autoregressive Model because it predicts one next pixel at a time.
CNN
PixelCNN uses masked convolutions in a CNN to limit what it can see.
Generative Model
PixelCNN is a Generative Model that learns image patterns and samples new images.