Adjust Brightness
Lighten or darken an image by shifting every pixel's brightness up or down with a single slider.
How it works
- 1
Drop your image onto the upload area and drag the slider left to darken or right to lighten.
- 2
A setting of 0 makes no change to the image, so you can compare before and after by toggling between 0 and your chosen value.
- 3
Click Apply Brightness to download the adjusted image.
Questions
What does this tool actually do to the pixels?
It adds a fixed value to every colour channel in the image. Positive amounts push channels toward white; negative amounts push them toward black. Channels that would exceed 255 or drop below 0 are clamped rather than wrapped.
Why is the output always a PNG?
PNG is lossless, so the adjustment you made is the only change to the image. Re-encoding as JPEG would add compression artefacts on top of the edit.
Does the image leave my device?
No. The brightness adjustment runs entirely in your browser using your device's resources. No file bytes are ever sent to a server.
Will transparency be preserved?
Yes. The alpha channel is never modified, so any transparency in the original image is kept exactly as-is.
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