Large image files slow down websites, bounce off email attachment limits, and eat up storage. Compressing an image reduces its file size, usually with little to no visible quality loss when done at a sensible quality level. This tool shows you a live preview of the resulting file size as you adjust quality, so you can find the right balance before downloading.
PNG is a lossless format by design, so it can't trade quality for smaller size the way JPEG or WEBP can. For real size reduction, convert to JPEG or WEBP instead.
Around 70 to 80% is usually the sweet spot: noticeably smaller file size with quality loss that's hard to spot at normal viewing sizes. The live preview lets you judge it yourself before downloading.
Yes, HEIC photos are decoded automatically and default to JPEG output, since that's where real compression happens.