Lib.rs

On a quick skim, "this sure looks like a PNG decoder": all the code is a reasonable kind of code for what it says it does, but I have not reviewed it for correctness.

I have also confirmed its functionality as a replacement for image's PNG support in my use case with a few small static PNGs.

Good things:

• There is no unsafe code.
• It seems to be taking care to return decoding errors rather than panicking, and the fuzz testing set up in the repository should be detecting such cases.

Potentially problematic:

• It allocates an amount of memory determined by the input image (using Vec::with_capacity()) without checks, so a malicious image could DoS via excessive memory use (zip bomb attack).