Image Brightness and Contrast guide
Adjust an image’s overall brightness and contrast locally, then export a new JPG, PNG, or WebP copy.
What this tool does
The Brightness and Contrast Adjuster applies two browser canvas filters to the complete image. Brightness scales all color channels: 100 percent keeps the source level, lower values darken it, and higher values lighten it. Contrast changes the distance between light and dark values: 100 percent is unchanged, lower values flatten tonal differences, and higher values increase them.
Both controls range from 25 to 200 percent. The transformation keeps the original pixel dimensions and exports in the source file’s supported web format. JPEG and WebP output use a high-quality setting, while PNG uses lossless encoding. Exporting creates a new file and does not overwrite the selected source.
These are global adjustments. The tool does not detect faces, recover clipped highlights, brighten only shadows, edit curves, correct white balance, or apply adjustments to a selected region. Increasing brightness cannot restore detail that was not present in the pixels, and strong contrast can remove subtle texture.
How to use it
- Add a JPG, PNG, or WebP image up to 25 MB to preview tonal changes.
- Move brightness below 100 to darken or above 100 to lighten.
- Adjust contrast separately.
- Select Apply adjustment after changing the controls.
- Download and compare the result with the original at full size.
Make small changes first. Screens differ in calibration and ambient lighting, so an image that looks balanced on one device may appear lighter or darker elsewhere.
Benefits
- Controls brightness and contrast independently
- Keeps original pixel dimensions
- Preserves PNG transparency where supported
- Supports three common web image formats
- Enforces a safe decoded-pixel limit
- Processes and exports entirely in the browser
Export considerations
Repeated JPEG editing causes additional lossy compression. Keep the original source and make final adjustments from it rather than repeatedly editing earlier exports. Color-managed desktop software may render wide-gamut or embedded profiles differently because browser canvas export commonly produces standard web-oriented pixel data and may not preserve every metadata block.