How to adjust brightness
1. Drop one or more JPG, PNG or WebP files. 2. Leave contrast at 0 and set brightness to +25 for a slightly light photo, or -25 if it is washed out. 3. Press “Adjust image” and download each file, or a ZIP if there are several.
0 and 0 is the original color, aside from JPG compression if you save JPG. Save PNG when you want the new pixels without another lossy pass. A video file is refused.
Brightness and contrast do different jobs
Brightness adds the same shift to every pixel, so a dark scan of a receipt can become readable. Contrast pushes colors away from middle gray, which helps a flat photo and can crush shadows if you go too far.
This is not grayscale and not invert. Those pages remove or flip hues. This page keeps the hues and moves how light they are. It does not crop or sharpen.
What the new file keeps
The pixel size does not change. Camera location is not copied, because the picture is drawn again on a canvas. A transparent PNG stays transparent. JPG paints empty pixels white before the levels, so a logo on a clear background gets a white box.
How to tell brightness from contrast
1. Leave contrast at 0 and move brightness until the dark area is readable. 2. Add contrast only if the photo looks flat. 3. Save PNG when you need the closest pixels, or JPG when you need a smaller file.
0 and 0 leaves the colors as they are, aside from JPG compression if you save JPG. Grayscale removes the hues. Invert flips them.