Adjust Image Brightness & Contrast
Brighten a dark photo, tone down a bright one or add contrast, and compare before and after as you move the sliders.
Runs in your browser. Your data is not uploaded.How our tools work
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How do I make a photo brighter?
Choose an image and move the Brightness and Contrast sliders, from −100 to +100, while comparing the before and after previews. Zero leaves the picture unchanged. When you save, the adjustment is applied to the image’s own pixels, so the downloaded file itself is changed, not just the preview.
- Select or drop an image.
- Move the Brightness slider to the right to brighten or to the left to darken, and Contrast to make it punchier or flatter.
- Compare before and after, then select “Apply and save” and download the image.
Formulas & Methods
Brightness
Example: +50 turns a channel value of 100 into 150
Contrast
Example: +100 doubles the distance from mid-grey; −100 makes everything mid-grey
Key features
Real adjusted pixels
The saved file contains the new pixel values, not a filter shown over the original on screen.
Live before and after
Compare the two side by side as you move the sliders; the After preview matches the saved file.
No quality lost while you adjust
The original is kept unchanged and the adjustment is rendered once when you save, instead of re-saving after every slider move.
Transparency kept
PNG and WebP transparency is untouched; only colours change.
Common uses
- Brighten an underexposed or backlit photo
- Add contrast to a dull or hazy picture
- Make a scanned document easier to read
Supported formats and limits
- Input
- JPG, PNG, WebP, GIF, BMP and AVIF up to 40 MB, plus HEIC where the browser supports it
- Output
- Same as original (other formats are saved as PNG), or JPG, PNG or WebP
What the two sliders can’t do
Brightness and contrast change the whole picture at once. There are no separate controls for shadows or highlights, no curves and no automatic fix, so a photo with a bright sky and a dark foreground may need a photo editor that can adjust parts of the image. The tool works on one image at a time.
Related tools
Frequently Asked Questions
Why do bright areas turn pure white?
Pixel values can’t go above white. Raising brightness or contrast a lot pushes the lightest areas to white, and that detail can’t come back. Smaller steps, such as +10 to +30, usually look more natural.
Do the sliders work like CSS brightness and contrast filters?
Yes. They use the same definitions as the CSS brightness() and contrast() filters, applied to the image’s colour values.
Does saving lower the quality?
A JPG is saved again at 95% quality by default, so apart from your adjustment the difference is very hard to see. PNG is lossless.
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