The icing on your cake can be any colour, but as the topper is made from very thin icing so dark colours or chocolate may not always be suitable. Try white chocolate instead or cut out a disc of white fondant to go behind the topper this should be about the same size and shape as the topper. Place the topper on the disc and put this on your cake. Otherwise you should apply it just before serving the cake, before the photo it has time to absorb the moisture.