I was curious as to how they could make such wonderful looking frames these days with such beautiful wood and such  perfectly mitred corners. So, I took one apart. Not hard to do…. they fall apart quite easily. Indeed they are the epitome of planned obsolescence.
The outside covering that looks so much like wood is actually a very thin coat of plastic, which gives the appearance of wood and allows for perfect mitres.
The inside is foam, made to deteriorate and fall apart. The foam is held together with metal pins at the corners , the plastic poured over the top.
Never was the saying “If it looks too good to be true it usually is”  more apropos! I make my frames from solid hardwoods, and avoid mitre joints as they are very weak: end grain wood cuts do NOT  glue well as the exposed pores absorb the glue . I hold my frames together solidly with 2 screws in each corner, hidden from view by a device known as a pocket hole jig. Far far stronger than any mitre joint.

Below is a picture of the “wooden” contemporary frame taken apart above.