  We introduce a simple and efficient lossless image compression algorithm. We
store a low resolution version of an image as raw pixels, followed by several
iterations of lossless super-resolution. For lossless super-resolution, we
predict the probability of a high-resolution image, conditioned on the
low-resolution input, and use entropy coding to compress this super-resolution
operator. Super-Resolution based Compression (SReC) is able to achieve
state-of-the-art compression rates with practical runtimes on large datasets.
Code is available online at https://github.com/caoscott/SReC.
