I think the idea of metapictures is a curious one. The idea of having pictures within pictures seems vague but as we were discussing Las Meninas, I thought it was interesting how my group saw so many different interpretations of the picture. While we originally thought the painter was the main painter in the image and not the man in the doorway, it was interesting how many variations of the image we saw which is, ultimately, what metapictures are.
Another one of the blogs was talking about multistability and claimed that they're pictures nestled within pictures and how you can't have one without the other. Then another blog was discussing how the main point of meta was not just self-realization but also the fact that they're open into audience interpretation. Which was the whole point of Las Meninas - there are so many ways to interpret the image because of the elements of mystery to it. What was he painting? Who is the focus of the image?
The idea of metapictures is self-realization of the pictures but also the self-reflection of your interpretation onto an image. The point of "The Duck-Rabbit" is that you can see one or the other, but when you force yourself to see one image, you can't see the other. Just like the whole concept of meta is forcing yourself to "come back to reality" in a way. In Ubiquitous Computing, they discuss the idea of a person going through a virtual world and essentially forgetting they're in one until they come to another piece of media that remind them of that. In Community, a sitcom on NBC (-ish), one character, Abed, continually reminds them of the basic plot points of a sitcom or whatever they're spoofing that reminds you you're watching a television show and that these people are actors.
The concept of meta is to force yourself to see reality in a certain way - do you see the rabbit or the duck? Do you see the painter painting an image in a mirror or a girl getting ready or a man in a doorway observing a scene?