Image Compressor

A photo straight from a phone is usually two to six megabytes, and almost nowhere needs that. An email attachment limit, a website upload form, a marketplace listing — all of them want something far smaller, and most of that size is detail no one will ever see at the size the image is actually viewed.

JPEG and WebP compression works by discarding information the eye is bad at noticing, and the quality slider decides how much. Around 75% is the useful setting: on a typical photograph the result is visually indistinguishable from the original at half the file size or less. Below about 50% you start to see blocky patches in smooth areas like skies and skin.

Resizing usually saves more than compressing does. A 4000-pixel-wide photo displayed in a 1000-pixel column carries sixteen times more pixels than it can show, so capping the width is often the single biggest win — which is why the maximum width option sits next to the quality slider rather than being buried.

PNG is deliberately treated differently. It is a lossless format, so the quality slider does nothing to it, and saving a photograph as PNG will usually make the file considerably larger rather than smaller. The tool says so rather than silently producing a worse result. PNG is the right choice for screenshots, logos and anything needing transparency, and JPG or WebP for photographs.

Everything happens on your device. The image is decoded, redrawn at the new size and re-encoded by your own browser, so nothing is uploaded, nothing is stored, and there is no queue and no file size limit imposed by a server. It also means the rotation data phones attach to photos is read and applied before re-encoding, so pictures taken sideways do not come out sideways.