It basically strips out unnecessary data from your image file. We use lossy compression here, which means it throws away details your eyes can't easily spot, giving you a drastically smaller file size.

If you want the absolute smallest file, go with WebP—it's incredibly efficient for the web. But if you're worried about older software or just need something that opens everywhere, stick with JPEG.

Honestly, unless you drop the quality slider way down, you probably won't even notice a difference. Sticking around 70% usually cuts the file size in half while keeping things looking crisp.