Attach your image to a white chocolate ganache covered cake (don't use milk or dark chocolate ganache as it can bleed through the image). Take a piece of baking parchment or wax paper slightly larger than the image and lightly grease the edges with Crisco/Trex and place over the image, the Crisco/Trex will help it to stick. Ice the whole cake with fondant as you normally would. It should be quite easy to find where the image is under the icing as you will have a little air pocket where the fondant hasn't stuck to the wax paper but just in case I mark the cake board underneath on the side that the image is on. Cut a X in the fondant being careful not to cut the image below. Peel back the fondant and with a pin carefully and gently lift the wax paper and remove it. Tear back the remaining fondant just a little smaller than the image below. Pinch, curl and shape the fondant edges to look like old paper and colour the edges with petal dust to give an aged look.