Brightness / Contrast
Brightness / Contrast is a free browser tool that lets you tune brightness, contrast, saturation. The image is decoded onto an HTML canvas in your browser and re-encoded there, so the picture is processed on your own device rather than uploaded. It is used most by bloggers shrinking hero images so pages load quickly. Reads JPG, PNG, WebP, GIF, BMP and AVIF where the browser supports them. Free, unlimited, and free of the upsells most tools of this kind carry.
Key features
- Reads JPG, PNG, WebP, GIF, BMP and AVIF where the browser supports them.
- Transparency in PNG and WebP is preserved; converting to JPG flattens it onto a solid background.
- Works on desktop, tablet and phone — no separate app to install.
- Built to do one job properly rather than twenty jobs badly.
How to use Brightness / Contrast
- Choose an image: Drop a picture onto the area above, or tap to pick one from your device or camera roll.
- Adjust the settings: Set the size, quality or format you need. The preview shows what you will get.
- Save it: Download the finished image — the original on your device is left untouched.
Frequently asked questions
- Can I use Brightness / Contrast on a phone? — Yes. Brightness / Contrast works in mobile Safari and Chrome, including picking images straight from your camera roll.
- Are my photos uploaded when I use Brightness / Contrast? — No. Brightness / Contrast works on a canvas inside your browser. The picture stays on your device and no copy is kept by us.
- Which image formats does Brightness / Contrast accept? — JPG, PNG, WebP, GIF, BMP and — in current browsers — AVIF. HEIC from an iPhone usually needs converting first.
- Will transparency survive? — Yes for PNG and WebP output. Saving as JPG has no transparency channel, so transparent areas become solid.