Repairing Under Exposed Images
compare the different methods in final result.

You made a picture of an object or person or landscape but the lighting isn't that good..what do you do now ?
Well this tutorial will teach you 3 methods of fixing up the image ( Don't forget one method is always the best, because this method is specially made for this kind of image Brightness and Contrast )
First Method Screen Layer
1) Right click and save the image to your computer.

Picture was taken but not enough light was exposed to it.
2) Open up the image in photoshop. Duplicate the layer ( Copy the layer ) by dragging it onto the new layer icon.

3) Now you change the layer options to screen

You can change the opacity if you want but with this image it isn't needed because the lighten was very bad.
Result of the first Method

Looks alot better doesn't it ?
Second Method changing Brightness and Contrast
1) Reopen the orginal image, this time you don't have to duplicate the orginal layer.
We going to work in the orginal layer.
2) Now goto Image - Brightness and Contrast

Now changing Brightness to a much higher level because you want the image to be alot brighter. By also moving the contrast level up you keep your depth of the picture.
3) I used these settings but this can be different for every picture

*tip* try moving around the brightness and contract to highest and lowest level now you will see what brightnes and contrast do to your image, funny isn't it ?
Now this is the end result of the second method

Third Method Using Curves
Go back to the orginal image you don't have to duplicate the orginal layer because we are going to work in the orginal layer
1) Goto - Image - Adjustments - Curvers ( or simply press CTRL+M )

2) Now adjust the settings until your sadisfied.

The final image will look like this

Well now the finished the tutorial we will compare the different methods

The brightness and Contrast is the best by far because it keeps the depth of the image and also make the image alot brighter ( which was the purpose of this tutorial )
This doesn't mean the other methods are crappy but the best method you can use for an image like this is just the brightness and contrast