Even though she'd been hugely popular ever since she was discovered by the Danish press, crown princess Mary also had the image of being mainly interested in horses, luxury and designer clothes. On top of that the thorough renovation of Frederik and Mary's palace at Amalienborg had a very high cost.
A crown princess needs a different image so court contacted a few tabloids and let them know they'd be able to make interesting photos at a certain moment, on a certain spot.
They saw Mary coming out of a private enterance of Kancellihuset carrying a barely filled garbage bag. Danish and international magazines all published this image with about the same comments: "the other side of a princess's life" ... "Mary's not too grand to take the trash out" etc.
Testimony by count Alexander von Schönburg: http://www.dailymotion.com/video/xf1tjt_royal-lovestory-frederik-mary-von-d_people