The "shell" material is set up to receive two separate colors from the main geometry nodes "control panel"- logo color 1 and 2- and uses two textures to determine where those colors get mixed on the shell, as well as to raise the "print" level via bumpmapping so that it reflects the lights appropriately.
In order to use a full color image logo "print", you'd need to switch the two textures and edit the shader node connections. Basically, you need a black-and-white image of the logo to use as a "mask" and a full-color image to determine the colors, and then link the output from the first "mix" node like so, that it replaces the color attributes coming from geometry nodes:
Hopefully, this will give you the desired result!
