convert-from-png-to-webp-and-resize-png-and-webp

# sudo apt install webp imagemagick parallel

# I ran this on 59 very high quality PNGs and my processor was maxing out for about a minute or so. I have an Intel Core-i7-8750H.

cd folder-with-huge-ass-png-files

# convert to webp in the same folder
parallel -eta cwebp {} -o {.}.webp ::: *.png

# Run resize commands in parallel (on many processes/threads). Adjust numbers to taste.
mkdir -p 512x-png && parallel -eta convert {} -resize 512x512 512x-png/{.}.png ::: *.png
mkdir -p 1080x-png && parallel -eta convert {} -resize 1080x1080 1080x-png/{.}.png ::: *.png
mkdir -p 1080x-webp && parallel -eta convert {} -resize 1080x1080 1080x-webp/{.}.webp ::: *.webp
mkdir -p 2160x-webp && parallel -eta convert {} -resize 2160x2160 2160x-webp/{.}.webp ::: *.webp