[header] How to adjust brightness in gimp [title] Select the layer you want to adjust. [step] After opening your image in gimp, click on the layer that needs adjustment in the layers dock. If you are adjusting the brightness of an image that hasn't been split into layers, the single layer " background " will be selected by default. 
[title] Open the " brightness-contrast " dialog box. [step] There are 2 ways to open this menu.