Image Brightness Adjuster ☀️
Adjust brightness of images. Make images lighter or darker with a slider.
Click to browse or drop an image here
JPG, PNG, WebPAbout the Image Brightness Adjuster
The Image Brightness Adjuster runs entirely in your browser. Drop or select an image, drag the Brightness slider between −100 and +100, and click Apply. Each pixel's RGB channels are multiplied by a factor of (1 + brightness / 100): 0 leaves the image unchanged, +100 doubles every value (brighter), and −100 drives all values to zero (black). Results are clamped to the valid 0–255 range. Download the result as a PNG. Nothing is uploaded to a server — all processing happens locally with JavaScript on your device.
How to use the adjuster
- Click the drop zone or drop an image file onto it.
- Drag the Brightness slider — positive to lighten, negative to darken.
- Click Apply to render the effect onto the image.
- Click Download to save the result, Reset to restore the original, or Clear to start over.
Frequently asked questions
What does the brightness value mean? 0 leaves the image unchanged. Positive values up to +100 brighten it; negative values down to −100 darken it toward black.
What is the output format? The download is a PNG file. This preserves detail and avoids compression artifacts.
Does this tool upload my images? No. All processing happens locally in your browser. Your image never leaves your device.
Will highlights get clipped? Yes, very bright values that exceed 255 are clamped. For best results, avoid extreme positive values on already-bright images.