This is an evolution of design for sure.  Taking the subject matter and blending it into the theme, is one of my favorite techniques.  I'm sure this fad will be short lived, but for now it is a great way to unify your design.  This design looks like four to five layers, gradient, and a mask.  You can find most of these resources through the links I have provided.  Making them blend together takes the touch though.  Great design! 

Her is the link to the designer of Expectations