We used Shutterfly, but it's ALL my wife's handywork.
The Shutterfly card has a large rectangular "hole" in it where you have them place your own photo. My wife made a collage into a single photo. That's our photo of the Castle, and then she superimposed and placed 4 other photos onto that one. She then saved it all as one photo. When I ordered from Shutterfly, I uploaded that one single photo, put in our text (printed in black), and waited for the mail to come. The fact that the blue sky background of our Castle photo is almost identical to the card color is pretty much a coincidence.