Add Layer Mask
1. Open Photoshop. Open Image to work with "Add
Layer Mask" button. Double click and unlock the Background
layer. Check out the detail
2. Click "Add layer mask" button. It is
second from the left at the bottom of the layer palette.
3. Once you click it you will find that foreground
and background colors become black & white. And the layer mask
thumbnail added to the image layer.
4. Select brush tool. Keep black as a foreground color.
5.Since we want to create vignette effect, start painting
around the sides of the image.
6. You will find that the image is as if erased but it's just hidden
behind the mask. Painting with white will reveals the image behind