Largely on grounds of cost, most people don't buy art in galleries. The chief vehicle for selling art on any mass scale is the museum gift shop. This is quite simply the most important tool for the diffusion and understanding of art in the modern world. Though it appears to be a mere appendage to most museums, the gift shop is central to the project of art institutions. Its job is to ensure that the lessons of the museum, which concern beauty, meaning and the enlargement of the spirit, can endure in the visitor far beyond the actual of the premises and be put into use in daily life. . . .
Postcards are successful and important mechanisms for improving our engagement with art. Our culture sees them as tiny, pale shadows of the far superior originals handing on the walls a few meters away, but the encounter we have with the postcard may be deeper, more perceptive and more valuable to us, because the card allows us to bring our own reactions to it. It feels safe and acceptable to pin it on a wall, throw it away or scribble on it, and by being able to behave so casually around it, our responses come alive. We consult our own needs and interests; we take real ownership of the object and, since it is permanently available, we keep looking at it. We feel free to be ourselves around it, as so often, and sadly, we do not in the presence of the masterpiece itself.
From Art as Therapy, a weirdly fascinating book that argues we should forget about understanding art as history or aesthetics and instead approach it according to what it can do for us emotionally.