When you want to cell shade a picture in Photoshop, the first thing you need to do is choose the color you want. Then, select the layer that will contain your picture. Choose the Edit menu and choose Cell Shade. Now, use the following steps to shade your picture according to your desired color:

  1. Choose a dark color for your background. This will help to create a more realistic look for your picture.
  2. Choose a light color for your foreground. This will give your picture a more cheerful feel.
  3. Use the slider on the right side of the Cell Shade dialog box to change how dark or light your background and foreground are respectively.