Best (Free) Image Compressor To Speed Up Website Load Time?

I’m not sure if I could be off topic, but would anyone here suggest a (possibly free) tool to compress images for the web so they are light but render perfectly at the same time?

With the awesome features of Enfold, I use it a lot to make stunning websites that are quite impactful. But I am always trying to reduce image size to the bare minimum while maintaining quality.

How do you make sure your images don’t take too long to load and don’t impact pagespeed and SEO too much?

Thanks!

Antonio