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Brightness

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Change image brightness online

Brighten image or lower brightness online: adjust photo exposure with a −100 to +100 slider. Live preview, PNG download in your browser.

What is image brightness adjustment?

Change image brightness by adding or subtracting a flat value from each pixel's RGB channels. Positive values brighten image tones; negative values lower brightness on overexposed areas. The same slider covers image brightener, picture brightener, lighten a photo, and increase brightness workflows—not monitor or screen brightness settings. Processing runs entirely in your browser.

Image brightener controls

Bidirectional brightness control to brighten image tones, lighten a photo, or lower brightness—not monitor settings.

  1. Brighten image and increase brightness: Positive slider values act as an image brightener for underexposed shots—preview before you clip highlights.
  2. Lower brightness on overexposed frames: Negative values tone down washed-out or low-brightness glare on overexposed photos.
  3. Brightness slider −100 to +100: Fine brightness control on PNG, JPEG, WebP, or GIF—one slider for brighten and darken.
  4. Live side-by-side preview: Compare original and adjusted as you drag, then download PNG.
  5. Large file support: Up to 15 MB and 8192 px edge for high-resolution images.

How to change image brightness

Steps for picture brightener and lighten-a-photo edits in the browser.

  1. Upload the image: Drop or click in the input panel (15 MB max).
  2. Adjust brightness: Move the slider above zero to brighten or lighten a photo; below zero to lower brightness.
  3. Preview the result: Compare original and adjusted side by side.
  4. Download PNG: Save when the preview matches your goal.

Tips for brightness adjustments

Get better results when changing brightness.

  1. Adjust in small steps: Move the slider gradually to avoid clipping highlights or crushing shadows.
  2. Check both extremes: Look at bright and dark areas in the preview for lost detail.
  3. Use PNG for transparency: Alpha channels are preserved when adjusting brightness.
  4. Start from original: If results look wrong, re-upload the original and adjust fresh.
  5. Combine with other tools: Use /change-contrast for midtone adjustments or /lighten-image for white blending.
  6. Match exposure first: Brightness is a quick fix—for serious work, fix exposure in your camera or RAW editor.

When to use an image brightener

Typical jobs for brighten image edits and brightness control on photos.

  1. Underexposed photos: Brighten image shadows with positive values—picture brightener workflow for dark indoor shots.
  2. Overexposed images: Lower brightness on blown highlights when you need less low brightness glare in exports.
  3. Screen captures: Adjust brightness for better readability in presentations.
  4. Product photos: Match brightness across multiple product shots.
  5. Social media images: Quick brightness fix before posting.
  6. Document scans: Brighten faded scans or darken washed-out copies.

Why use this brightness tool

Benefits over full editing software.

  1. Private: Images stay on your device—no server upload.
  2. Instant preview: See changes in real time as you adjust.
  3. No install: Works in any modern browser.
  4. Free: Unlimited adjustments and downloads.
  5. Simple: One slider vs complex curves or levels.
  6. Bidirectional: Brighten or darken in the same interface.

Technical details

How brightness adjustment works.

  1. Algorithm: RGB offset: channel = clamp(channel + (brightness / 100) × 255, 0, 255); alpha unchanged.
  2. Rendering: Canvas 2D getImageData / putImageData.
  3. Input limits: 15 MB; longest edge 8192 px.
  4. Output: PNG via canvas.toDataURL.
  5. Privacy: Client-side only—no upload.
  6. Browser support: Chromium, Firefox, Safari with Canvas 2D.

Frequently Asked Questions

Have questions? We have answers.

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