Compression guides

Most image files are far bigger than they need to be. A phone photo is usually 3–5 MB, while a website, an email or an online form needs something between 20 KB and a few hundred KB. The guides in this section explain what actually makes a file smaller — pixel dimensions, format and quality — and in which order to change them so the picture still looks right.

Start with the guide on compressing without visible quality loss if you are new to this. If you have a hard limit to meet, the compress-to-size tool lets you type the target in KB, and the website guides cover how image weight affects page speed and Core Web Vitals. Everything here works in your browser, so you can test each tip on your own files as you read.

A quick rule of thumb used throughout these guides: resize first, then compress. Shrinking a 4000-pixel photo to the size it will actually be shown at removes most of the weight before quality settings even matter, so the final file looks cleaner at the same KB. For many files at once, bulk compression applies the same settings to a whole folder and gives you a single ZIP.