That image is still highly misleading, you can see from the overlayed optical image that the CPU is not coated.

Ideally you'd want to coat any metal surface with black epoxy, and set the IR camera Emissivity Coefficient to 0.9 (the coefficient for black epoxy).

Why would the overlay need to be with the board that had a coating? Buy two boards, cover the parts on one board that are silver, shoot IR. Use second board for visible wavelength photo, combine for a beautiful overlay result.

Why would you assume that they are different boards?

It's not an assumption, it's a suggestion for making an thermal/visible light overlay photo where the IR photo shows only emitted light.

Wouldn't that change the heat dissipation characteristics and skew the results? Is a metal surface coated with epoxy exactly the same (from transmission, convection and radiation point of views) as a naked metal surface?

How was that accomplished? Extremely nice image!

Many IR cameras have actually two cameras, a normal optical one with high resolution (~10^3 x 10^3), and the IR one (microbolometer) which is low resolution (~10^2 x 10^2). They ensemble the two pictures later and produce these results.

I have the cheaper Seek imager, which just has a low res IR camera. Can’t afford the fancy tools where not needed! I mostly use it to check the house for air leaks and thermal issues.