Three questions and you are done
Which image format do I need?
Answer three things about your image and we will tell you the format, quality and size that suit it. Then we open the tool with all of that already set.
The full table, if you would rather decide yourself
The assistant guesses nothing: it applies these rules, the same ones anybody who works with images every day would use.
| Destination | Photograph | Logo, chart or text | Quality | Size |
|---|---|---|---|---|
| Website or blog | WebP | PNG | 80 | 1600 px |
| Send to someone | JPG | PNG | 85 | 1920 px |
| Form or application | JPG | PNG | 80 | 1280 px, under 200 KB |
| JPG | PNG | 92 | Keep as is |
And above all of that sits one rule that overrides the rest: if you need a transparent background, JPG is out, because it does not support transparency and anything transparent comes out filled with white.
Why those questions and not others
The destination decides the format more than anything else. The same photo wants to be WebP on a website (so it weighs as little as possible) and JPG in an email (so whatever software is at the other end can open it). There is no best format: there is a right one for wherever the image is heading.
What is in the image decides whether a lossy or a lossless format suits it. JPG and WebP work by grouping areas of similar colour, something photographs hide very well and text and fine lines give away immediately, with halos and dirt around the letters.
Where the file comes from does not change the output format, but it does change the tool: a HEIC from an iPhone has to be decoded first, and a downloaded .webp usually arrives with the urgency that plenty of desktop software will not open it.
The settings it leaves ready for you
When you press the button, the tool opens with the format, the quality and the maximum size already selected, and tells you they came from the assistant. You can change any of the three: the images are reprocessed on their own.
Quality moves between 80 and 92 depending on the destination, which is the band where the loss does not show. Maximum size caps the longest side, and that is where nearly all the weight saving comes from: a 4032 px phone photo shown in an 800 px column downloads five times more data than is needed.
If you want the long reasoning, it is in the guides JPG, PNG or WebP and how to compress without it showing.
Frequently asked questions
What if I do not know where the image came from?
Pick “I do not know” and we will take you to the general converter, which accepts every common format and works out what it has in front of it on its own.
Why does it recommend WebP for the web but not for sending?
Because those are two different worlds. Every current browser displays WebP, so on a website it is the lightest option. Outside the browser, though, plenty of desktop software still will not open it, and an image the recipient cannot open is useless no matter how little it weighs.
Can I change the settings afterwards?
Yes. The assistant only presets the selectors; in the tool you can move the quality, the format and the size, and the images are reprocessed on their own with the new values.
Does it work without JavaScript?
The automatic calculation does not, but the decision table on this very page holds exactly the same rules and reads fine without JavaScript.