Most people have bought a cake with an edible image on it. Maybe it was a cake with the picture of Dora or Tweety Bird, or even a custom-made cake with a picture that had special meaning to someone. You can make these types of cakes inexpensively and right in your own kitchen.
Mix the butter cream frosting. Combine the shortening, butter and cream. Add the vanilla and the powdered sugar. Mix on high speed for 5 to 10 minutes. The frosting needs to be fairly thick. If it's not thick enough, add more powdered sugar until you have the consistency needed. Set aside.
Print out the picture you want to apply to your cake. Make sure that the picture is in reverse, like looking at a mirror. If you are just beginning, try a simple picture before starting a more detailed one.
Place your picture on the cutting board and a wax paper on top of it. Tape them both to the cutting board to prevent slippage when tracing and coloring. Use a black food pen to trace the outline of your picture onto the wax paper. You can also use black icing gel. Be careful to stay on the lines and not to blur them.
Fill the spaces inside of the outline with colored icing. You can either use food coloring or buy the tubes of colored icing gel. Stay inside the lines while coloring the picture. When you have finished coloring your picture, gently press the back of a spoon on the picture. This will help the colors to settle within the grooves, giving a smooth finish. Don't press too hard or your colors will blend together.
Cover the back of the colored picture with an even coat of frosting — the same color of the frosting on your cake. Make sure you spread frosting onto the wax paper around the picture so the edges all show the same color.
Set the cutting board in the freezer for a couple of hours, and then remove. Turn the frozen frosting picture over, and place on the iced cake. Gently press onto the cake, and remove the wax paper. Be careful when removing the paper that you don't pull too hard and pull the image up from the cake. Finish decorating the cake any way you like.