From here you have several options. It usually bleaches out the image but it is the second fastest way to change the image s brightness. You can use the tool bar that comes up with two different bars on it to make your variations. The second bar controls the contrast and this makes the colors in the image brighter so be careful how bright you make this for it will also make you lose quality after so much. You have to play with each of the bars to get the image quality for which you are looking.
Levels are the most complicated option yet the best to use.
But, levels are the best option to use in Photoshop to get the image brighter without losing your information. The difference is that this will change the shadows, mid-tones, and the highlights of the image to give you the image quality you want. This is what auto levels uses but it takes the bulk of the information and adjusts the levels accordingly. By changing the levels yourself, you can select the chunks of information you want to disregard or keep. Figure 1 explains how the different triangles work.