@thelightstain wrote:
Thanks for clearing things up. What I found in go is guetzli and I don’t believe it handles progressive encoding. Mozjpeg would be a nice candidate, but still in C (++).
I don’t know if it is worth the high cost you mentioned ( I assume site generation speed). Sure for a highly optimized site containing many images it might help allowing hugo to do all the work and eliminate the need for additional (external) image processing tasks.