How to brighten a dark photo
Upload your picture and the Adjust tab opens with brightness already raised to 115 percent, a gentle lift that suits many indoor and evening shots. Move the slider between 0 and 200 percent: 100 is the original, values above it lighten every pixel and values below darken it. Watch the preview until faces and important details are clear, then download.
Brightness scales all tones by the same factor. That makes it a simple, predictable fix for a photo that is evenly too dark or too light, such as a picture taken in a dim room or a scan that came out grey.
How much to adjust and what to watch for
Small changes go a long way. Most photos look natural somewhere between 90 and 130 percent. Past that, bright areas such as skies, windows and white shirts start to clip to pure white and lose all detail, and that detail cannot be recovered later. Darkening below about 70 percent tends to crush shadows into flat black.
Brightening a very dark phone photo also reveals noise, the grainy speckles cameras produce in low light. If that happens, a slightly smaller lift combined with a small contrast increase often looks cleaner than brightness alone.
Brightness versus contrast
Brightness moves the whole image lighter or darker. Contrast changes the distance between light and dark tones. A photo that looks grey and hazy usually needs more contrast, not more brightness, while a photo that is simply too dark needs brightness. Both sliders sit together in the Adjust tab, along with saturation, so you can balance them in one place. The final file is rendered on the server; PNG stays PNG and other formats download as JPG.