[wooosh]

Unfortunately I haven’t had the time to do a proper benchmark, and the fpng test executable only decodes/encodes a single image which produces very noisy/inconclusive results. However, I’m under the impression that it doesn’t make a large difference in terms of overall time.

fpnge (which I wasn’t aware of until now) appears to already be using a very similar (identical?) algorithm, so I suspect the relative performance of fpng and fpnge would not be significantly impacted by this change.

[Nyan]

As someone who has been recently optimising fpnge, Adler32 computation is pretty much negligible regarding overall runtime. The Huffman coding and filter search take up most of the time. (IIRC fpng doesn't do any filter search, but Huffman encoding isn't vectorized, so I'd expect that to dominate fpng's runtime)