I am compressing 200x200px and 800x800px images. For those sizes, while the encoding speed is slow for real-time use cases, for product images it's completely i

I am compressing 200x200px and 800x800px images. For those sizes, while the encoding speed is slow for real-time use cases, for product images it's completely irrelevant - anything under 1 minute/image gets a pass and lower, generally, isn't better (or worse). I'm looking at absolute image quality/byte and it's even more niche than that - it's bytes to pass a threshold of acceptable quality (85 on Guetzli IIRC). I don't care about very low or very high qualities. In terms of absolute bytes to pass this threshold, Guetzli felt the best when I was doing the research (~ mid-2017). I don't have any hard data to back this though - I did the experiment with 5-6 different product images, drew the conclusion and started using Guetzli.