I've had a couple people inquiry exactly what I did to achieve this effect. So here are some better pictures.
Here is the before pic for reference.
Here are the dollar store acrylic single photo frames.
When turned on their sides, they support the weight of any picture frame glass insert. By using different types of acrylic frames, you can achieve various heights.
And the end result. Of course the possibilities are endless when using different size picture frame inserts and acrylic frames. Good luck!