This free WordPress image optimisation plugin is easy to configure and is the best at maintaining high quality with while reducing image file size. The paid version is affordable and even better. Their CDN for images is a game-changer for serving images fast to people on every continent.

When I was new to the EWWW IO CDN, I had a problem caused by my lack of understanding. EWWW's Adam was great at problem-solving, with prompt advice customer service that I received.
I highly recommend the EWWW image optimisation plugin.