Cody here (the guy who rendered this).
I made the VRC animations
Clean Sweep and
Round Up.
This render was made with 3ds max 2014 using the mental ray renderer. It utilized three of my four rendernodes which each pack 2x Intel Xeon i7 E5540's + my 4.3 GHz (OC) i7 2700k workstation. Even with all that power this render took a very long time to complete (I ran it overnight).
This isn't surprising, it's a 4k high quality render with DOF and a large trace depth. Believe it or not I've had worse renders. This
render of the Toss Up field featured segmented shadows, caustics and volumetric lighting - even @ 1080p it took the entire farm over a day to render.
Andrew's work has always been amazing, rendering it has always been fun.
Regarding the PNG, that is the raw file 3ds generated. It's so big because it's a 16-bit image not an 8-bit like traditional graphics (IE 16 bits per color channel not 8). My 10-bit monitor can display some of this advanced color depth. I gave Andrew the whole image because why not? Fun fact, mental ray actual computes in a 32-bit color-depth.
But yeah a more web-optimized version could be made, PNG or JPEG - doesn't really matter, I like PNG better.
-Cody