According to The Sun, the royals sent the card to everyone who wrote them notes of congratulations for their marriage.
The black and white wedding photo they chose, taken by Alexi Lubomirski (who also shot their stunning engagement photos), is a candid moment between the couple, who are pictured sitting on the steps of Windsor Castle as they took a minute to themselves amid the formalities.
Lubomirski has previously spoken of how he captured the picture.
"It was just one of those magical moments, when you're a photographer and everything falls into place," he explained to The Sun.
"The sun is setting right just over the top of Windsor Castle just behind them, it was just the most serene, beautiful light, they're in love, walking around this beautiful garden.
"I said just before you go in, let's sit down on these stairs, and she just slumped in between his legs.
"They were just laughing because they were joking about how they were exhausted and finally it was over."
