Adjust brightness, contrast and colour
Brightness, contrast, saturation, warmth, sharpening and invert, previewed live and made on this device.
- Nothing is uploaded
- Works offline after first visit
- Open source
- No watermark · limit is your device’s memory; phones hold less
Brightens, adds contrast, changes colour, warmth and sharpness, or inverts a photo, with a live preview, for one image or a batch. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after one visit to save itself for offline use, and then it works offline.
Done
Open the network tab. Your files never appear in it.
Add files and run the tool to see every request this tab makes.
Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.
How it works
- Drop one or more photos (JPG, PNG, WebP, HEIC, AVIF or JPEG XL).
- Move the sliders while you watch the preview; press and hold Hold to compare to see the original.
- Press Apply. Every photo you dropped gets the same settings.
In your browser, not on a server
Your browser decodes each photo (libheif or the Squoosh decoders step in for HEIC, AVIF and JPEG XL) and draws it on a canvas in your tab. Brightness is a gamma curve and contrast an S-shaped stretch around middle grey, both applied through a 256-entry lookup table per channel; warmth shifts red against blue, saturation mixes each pixel with its own Rec. 709 brightness, and sharpening is an unsharp mask: the picture plus a share of its difference from a blurred copy. The browser then saves the canvas as JPG, PNG or WebP.
Compared with upload-based tools: Online photo editors upload the picture for a slider move a phone could do offline, and many add a watermark or keep the upload. Here the photos stay on your device, a whole batch gets the same settings in one go, and the result is compressed only once.
Verify it yourself. Give the page a short while after one visit to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.
Questions
Are my photos uploaded?
No. Each photo is decoded and adjusted pixel by pixel on a canvas in your tab, and saved by your browser. Your files are not uploaded, so it works offline after one visit and a short wait.
Why does brightness not wash out the whites?
Brightness here is a curve, not a flat addition: it lifts the dark and middle tones while black stays black and white stays white. Adding a fixed amount to every pixel, as simple editors do, turns bright skies into flat white patches.
How much should I sharpen?
For a photo straight off a phone, 20 to 40 is usually enough. Look at edges such as hair or text in the preview: once a thin bright halo appears along them you have gone too far. Sharpening cannot rescue a badly blurred shot; for a small or soft picture the AI upscaler adds real detail.
Can I adjust many photos at once?
Yes. Drop them all; the preview shows the first, and the same settings are applied to every one when you press Apply. That suits a set shot in the same light, such as product photos or a batch of scans.
Is the camera data kept?
No. The adjusted photos are written fresh from the canvas, so location, camera and date metadata are not in them.
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Add border to image
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Popular conversions
- HEIC to PNG
- HEIF to JPG
- PNG to JPG
- JPG to PNG
- WebP to PNG
- WebP to JPG
- PNG to WebP
- JPG to WebP
- AVIF to JPG
- AVIF to PNG
- Sharpen image
- Brighten photo
- Invert image colors
- Color picker from image
- Color palette from image
- HEX color from image
- Blur text in image
- PNG compressor
- Reduce PNG size
- GIF compressor
- Reduce GIF size
- Make background transparent
Guides
- How to brighten a photoA dark photo can usually be saved in a few taps. Here are the steps on each device, and a way to fix a batch of them at once.