The biggest smallest PNG

A few days ago, my former coworker Evan Hahn posted “The world’s smallest PNG”, an article walking through the minimum required elements of the PNG image format. He gave away the answer in the very first line:

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However (spoilers!) he later points out that there are several valid 67-byte PNGs, such as a 1×1 all-white image, or an 8×1 all-black image, or a 1×1 gray image. All of these exploit the fact that you can’t have less than one byte of pixel data, so you might as well use all eight bits of it. Clever!

However again…are we really limited to one byte of pixel data?
↫ Jordan Rose

You know where this is going.