Free Bulk Brightness & Contrast Editor

Adjust brightness and contrast of multiple photos at once. Auto-equalize lighting across all images to make them visually consistent. 100% free, 100% private.

100% Private — processed in your browser

Click or drop your images here (up to 10)

Tap here to load your images

How to Adjust Brightness & Contrast in 3 Steps

Fix lighting across multiple photos — completely free and private. No account needed.

1. Upload Your Images

Click the upload area or drag and drop up to 10 images. Your files stay on your device — nothing is uploaded to any server.

2. Adjust or Auto-Equalize

Use the brightness and contrast sliders to fine-tune each image, or click "Auto-Equalize" to automatically match lighting across all photos.

3. Download

Download images individually or grab them all at once as a ZIP file. Adjustments are baked into the output — no quality loss.

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Frequently Asked Questions

How does the brightness and contrast editor work?

The editor uses your browser's built-in Canvas API and CSS filters to adjust brightness and contrast. Everything is processed entirely on your device — no data is sent to any server. You see a live preview as you move the sliders, and the final export bakes the adjustments into a new JPEG file.

Are my images uploaded to a server?

No. Everything runs 100% in your browser. Your images never leave your device. This makes the tool completely private and works even offline once the page is loaded.

How does Auto-Equalize work?

Auto-Equalize analyzes the average perceived brightness (luminance) of each uploaded image. It then calculates a target brightness — the average across all your photos — and adjusts each image's brightness slider so they all converge to the same lighting level. This is perfect for product photos, event shots, or any set of images taken in different lighting conditions.

Can I adjust each image individually?

Yes! Uncheck the "Apply same adjustments to all images" toggle, then click on any image thumbnail to select it and adjust its brightness and contrast independently. Each image remembers its own slider values.

Can I adjust multiple images at once?

Yes! Upload up to 10 images and adjust them all simultaneously. With "Apply same adjustments to all" enabled, moving a slider changes every image at once. You can also use Auto-Equalize to let the tool automatically match brightness across all photos.

What image formats are supported?

You can upload JPEG, PNG, WebP, and HEIC/HEIF images. Adjusted images are exported as high-quality JPEG files (92% quality) to keep file sizes reasonable while preserving visual quality.

Will adjusting brightness/contrast reduce image quality?

The tool processes your images at their original resolution. The output is saved as a JPEG at 92% quality, which is visually indistinguishable from the original for most images. For best results, start with high-quality source images.

What is the difference between brightness and contrast?

Brightness makes the entire image lighter or darker uniformly. Contrast adjusts the difference between the lightest and darkest parts of the image — higher contrast makes lights lighter and darks darker, while lower contrast makes the image look more flat or washed out. Together, they're the most fundamental tools for fixing photo lighting.