For the usual case of DEFLATE-based formats (PNG, ZIP) and JPEG, ECT [1] is the best available tool; to my best knowledge it dominates the entire Pareto frontier in this area, beating Zopfli and ADVPNG/OUT for most cases. If this software is still being maintained, it would be a good choice to switch to ECT now.

[1] https://github.com/fhanau/Efficient-Compression-Tool

I’m curious to know how this compares to other compression tools like brotli, zstd, and xz.

I guess I’ll have to include it in my own benchmarking suite I’m developing.

Nice. I could see plugging this into GenAI interfaces generated on the go