The main reason is trying to catch the atmosphere and create this with just Lego bricks. Playing with real light and shadow is allowed, Photoshop is not just like modifying bricks or minifigs. And I'm very strict to myself. No Lego piece was harmed in any way. Even the minifig ropes can be ironed and will be perfectly smooth again. Some pieces are very old, some from today's sets, but everything on this picture has originally come from Lego.
Here you are "The Love Letter" by Johannes Vermeer - in bricks.
This scene is also playable. At least even Vermeer painted an open end to his story. The love of a girl of virtue in her domestic surrounding full of symbols of love and sex got a letter from her lover. But... is it really a love letter? Or a break up letter? We will never come to know, but we can play the story on our own.
And finally... compare it yourself.
Photograph of the painting by Rijksmuseum.
Bigger picture of the photographs on flickr.