Image Compressor

Big photos slow down web pages, bounce off email limits and get rejected by upload forms. This compressor re-encodes JPG, PNG and WebP images at a quality you choose — or searches for the best quality that fits a size such as 200 KB — and can cap the width and height at the same time. Everything runs in your browser, so the files never leave your device.

How to use this tool

1. Drop one or more images into the box; the same settings apply to every file.
2. Choose “Quality setting” and a quality (75% is a sound default), or “Target file size” and the size each file must stay under.
3. Keep the original format or switch to JPG, WebP or palette PNG; optionally set a maximum width or height.
4. Compare the before and after sizes under each image, then download the files one by one or as a ZIP.

Formula

Saving = (1 − compressed bytes ÷ original bytes) × 100%

In target mode the tool tries quality 95%; if that is too big it halves the quality range seven times (binary search between 40% and 95%) and keeps the highest quality that fits. If even 40% is too big, it scales the image down and searches again, because a smaller sharp picture looks better than a blocky full-size one; quality only drops below 40% when the image cannot shrink any further. PNG output is reduced to a 256-, 128- or 64-colour palette with Floyd–Steinberg dithering (scaling down before using fewer colours) and written as an indexed PNG; transparency is kept.

Example

A 4032 × 3024 px phone photo of 3.4 MB, saved as JPG at quality 75 with a maximum width of 1600 px, comes out at 1600 × 1200 px and roughly 250–350 KB — around 90% smaller — and still looks sharp on a laptop screen.

Which format to choose

Photos: JPG for maximum compatibility, WebP for about a quarter less size at the same look (Safari cannot encode WebP; the tool tells you). Screenshots, logos and graphics with transparency: palette PNG, which often shrinks them by 50–80% with no visible change. GIF, BMP, AVIF and HEIC sources are saved as JPG, or as PNG when they contain transparency.