1. Choose a photograph:
   
   
   
2. Scan a line drawing:
   
   
   
3. In PhotoShop, import the line drawing and switch into RGB mode. Use the "magic wand" to select white space. Press "delete". Only the lines should remain.
   
   
4. Using the "brush" and the "fill", add color:
   
   Use the brush to close regions; then apply the fill/bucket tool to color entire regions at once.
   
   
5. Copy the now-colored cartoon to a new layer above the photograph, resize, and move:
   
   (I cropped the photo in this case.) Then use the eraser on the cartoon layer to remove portions that should be behind objects in the photograph.