Adjust Image Brightness and Contrast

What this tool does

Adjust image brightness here without opening an editor, uploading the photo or making an account. Four sliders sit side by side: brightness, contrast, saturation and warmth, with an Auto levels button for a quick fix. The preview updates as you drag, Show original flips back to the untouched image, and the download keeps the full original resolution.

How to brighten a dark image

1. Add the image. Drop it onto the page, paste it, or choose it from your disk. A frame grabbed from your video works as well as a photo.
2. Try Auto levels first. It sets the darkest tones in the picture to black and the lightest to white, which is often all a flat or underexposed shot needs. Press it again to turn it off.
3. Fine-tune with the sliders. Brightness lifts or lowers every tone by the same amount. Contrast pushes tones away from mid-grey, so darks get darker and lights get lighter. Saturation makes colours stronger or more muted, and warmth shifts the picture towards orange or blue.
4. Watch the clipping readout. The stats show how much of the image is pure white or pure black before and after, and a warning appears when an edit clips noticeably more.
5. Download as JPG, PNG or WebP. A PNG keeps any transparency.

Brightness or contrast?

Raising brightness on its own lifts the shadows and the highlights together, so a dark frame gets lighter but also greyer and flatter. Adding some contrast at the same time restores the depth. In a thumbnail the usual aim is a subject that separates clearly from its background at a small size, which is a contrast job more than a brightness one. Saturation is the easiest slider to overdo: skin tones go orange well before the rest of the picture looks wrong, so check a face at feed size before you commit.

All four adjustments, nothing uploaded

Many of the pages that rank for this job split brightness, contrast and saturation across separate tools, so you download and re-upload between each one, and others are full editors that ask for an account or push an app. Here every adjustment is on one page and is applied by your browser on your own device, so the image never leaves it, and there is no watermark on the result.

For help picking colours that stand out, read the best colours for YouTube thumbnails, or start with a better source photo using how to take photos for YouTube thumbnails. To check the adjusted image at feed size, use the thumbnail preview, or generate a thumbnail from scratch.

Last updated October 31, 2026.