Compared with other tools

An image is as heavy as its pixels, its quality and its format together. Fix one and the other two keep the waste. Each common tool fixes one of the three levers, or measures without deciding.

• Compressors squeeze the file you hand them. They do not learn how wide the image is shown. A 6,000 px logo in a 150 px slot stays 6,000 px, only better compressed.
• Image CDNs and next/image resize on request, but only to the widths your sizes attribute asks for. A wrong or missing sizes makes every phone fetch a file several times too wide.
• Lighthouse flags oversized, poorly encoded and old-format images, at one viewport per run, with a fixed estimate. It tells you something is wrong. It does not tell you which sizes or quality to set.
• ImgTune measures size, quality and format together, per image, on the live page at six viewports. A saving counts only when SSIMULACRA2 says nobody can see the difference. Your AI agent makes the change from the hint, and a rescan checks it.

ImgTune does not replace a CDN or a compressor. It tells you which sizes and quality to use with them, and it checks the result.