How to Fix an Overexposed Digital Photo
If you accidentally overexpose a photo with your digital camera, you can easily fix it with a duplicate layer and the proper blend mode. As long as none of the overexposed highlights are completely blown out to white, you can save the image.
These steps use Photoshop Elements but most image-editing programs share similar procedures
1Open your image editor and choose File→Open.
The Open dialog box appears. Navigate to the image you want to edit and click OK. The image opens in your image editor.
3In the Layers Palette, change the duplicated layer’s blend mode to Multiply.
This blend mode darkens the image considerably.