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Aren't photographs always 2D though, even in our three-dimensional real life?
It could be Medium Blending if you literally mean that someone takes a photo with a Polaroid camera, and it spits out a 2D sprite asset that stands out against the 3D CGI assets. That'd be really weird and a huge Special Effects Failure. But it doesn't count just because a photograph happens to be a flat object.
That thing where a movie uses CGI but any photographs taken are 2D.