A console application that uses the MozJpeg library to compress all the image blobs in the Sitecore Blob table.
See this post:
https://dev.to/danielrolfe/honey-i-shrunk-the-sitecore-db-preparing-for-sitecore-10-8bh
Dislaimer: This is not production ready code. It's for test and evaluation purposes only. Translation: It may suck.