It turns out PICT is one of those formats that is just crap. It’s needlessly complex and for every way of encoding something, there is potentially 2 or 3 others ways of doing so as well. On top of that, some areas of the spec seem to be vague, repetitive or contradictory and just there to make life hell.
I’m not a fan of this format at all.
Why the rant?
So it turns out EV Nova’s data files use the PICT format for many things. UI graphics, targeting graphics, ship icons, landing screens, etc. Lots of them. However there currently appear to be 3 types of PICTs used. I’ve accounted for two of them, but the final one is infuriating, as finding documentation or reasons is impossible. I doubt this is the fault of the original designers. It was the software they used that did the encoding.
Single pixel width images are the problem. These are used by the middle graphics of buttons in the UI. These fail to parse properly.
On the bright side…
So as I’ve been searching for more information about this format, I have been able to find something interesting thankfully.

This is buried in the depths of the system, nested inside other frameworks. It’s the QuickDraw framework. In which all the functionality for QuickDraw and it’s format exists. This framework is deprecated and use of it is not really recommended these days. It will limit the app to 32-bit only and will not handle retina displays correctly.
But it does mean I have a reference point. How?

Hopper Disassembler! A great tool for peeking inside and inspecting compiled binaries. That QuickDraw framework includes a binary that I am able to pull apart and study. Hopefully some of the secrets of the Picture resource will begin to reveal themselves.