What is in a Metapicture?

What is the ultimate goal of a metapicture? Is the image within the image created to disrupt the genre? If so, who gives meaning to the  disruptive image, us as viewers or the artist themselves? The La Meninas painting prompted me to ask these questions. Why would the artist include himself in the picture? If we look at the definition of a Metapicture in a surface manner we would assume that the artist has placed himself in the image only to disrupt the image. But when we take a deeper look at exactly what makes a Metapicture,  it would appear that the artist did this in order to make a cultural statement about traditional art and how we view it.  It is Mitchell's statement that  “The metapicture is a piece of moveable cultural apparatus, one which may serve a marginal role as illustrative device or a central role as a kind of summary image…encapsulates a whole episteme, a theory of knowledge.” ( Mitchell 49) that leads me to this conclusion.  

Metapictures are created in order to bring light to an episteme.