The colour of the two pictures cannot be directly compared, due to lighting and camera differences. Also, Dick used Mobil oil, while I used Aspen fuel which is not gasoline, but pure alkylate fuel. Both oil types are fully synthetic Jaso FC class.
Like I stated before, it is more important to look for the shades of gray and the transitions on central electrode, isolator, plug body and ground strap, which tell the tale on heat range, mixture strength and ignition timing. Some engine tuners can even discriminate the idle mixture strength. (I can not)
In general, oil presence and oil type does make a difference in the plug colour, and oil content has remarkably little influence. This is not surprising, because so little of it is in the mixture, even at high mixing ratios. At high oil ratios like 1:20, the oil content tends to foul the plug sooner when the plug is of a cold type like in racing engines with engine cold. When the engine is up to working temperature, the plug is selfcleaning, and fouling does not occur anymore.
In our aircraft engines this is not the case, while we run medium heat range plugs that heat up very fast.