Guides
What we have learned building these tools — formats, compression and privacy, explained without filler.
Every one of these guides came out of a question somebody actually asked, usually while stuck. Why will this photo not go under 100 KB? Why does my iPhone picture refuse to open on Windows? Is it safe to put a passport scan through a website? The answers turn out to be more interesting than the questions, because they come down to how image formats work — and once that clicks, most of the everyday problems stop being mysterious.
They are written by the person who built the tools, so they include what a product page leaves out: where a technique stops working, when the honest answer is that a file cannot get smaller without visible loss, and which limits come from the format itself rather than from the software. No filler, no affiliate links, and no advice we would not follow ourselves.
- How to compress an image to an exact size in KBGovernment portals and job applications often cap uploads at an exact size in KB. Here is how those limits work, what resolution actually fits, and how to hit the target without wrecking quality.
- HEIC vs JPG: why your iPhone photos won't openYour iPhone saves photos as HEIC, and Windows, older software and many web forms refuse them. Here is what HEIC actually is, when to convert, and how to stop the problem at the source.
- PNG vs JPG vs WebP: which one should you use?A practical guide to choosing between PNG, JPG and WebP based on what is actually in the image: photos, logos, screenshots or transparency.
- WebP and AVIF explainedWebP and AVIF promise smaller images than JPG. Here is what they really save, where they break, and a practical rule for deciding which format to serve.
- Why in-browser image processing is more privateMost online image tools upload your files to a server. Browser-based tools do not. Here is the difference, why it matters for documents and ID photos, and a test you can run yourself.