To bake a cake with an image inside first you will need to bake a slab of cake to cut out the images. Make it pretty thin. I've used a large baking sheet for mine.
You will also need a silicone pan 3 inches deep and some kabob skewers cut to fit tightly inside the pan.
Place skewers through the cutouts.
Here I forgot to take a picture but you will want to cover the cutouts with the remaining batter. Make sure they are completely covered, then bake until done. It may take longer than usual for your cake to bake. Mine took nearly 1 1/2 hours before it was done.
Don't forget to remove the skewers :)
When finished you will have a cake with an image inside when cut.