The color of the tiny heart is echoed by the colors of the door frame and the woman's jacket. She probably loves the taste of what she is drinking at the moment, and the symbolic heart perfectly compliments that feeling.
You also might want to consider trimming the image from the bottom, making it even more horizontal. Such a crop would also remove the tin foil clad sandwich from the scene. You may well see the relationship between the heart and the drink become even stronger.
