It’s easy to explain really.
The firetruck was a federal one hence the Q on the side. They have to have clearance to be on that tarmac. It was pulled because it was a Getty image and they do not like people using their stuff without approval
The other image was an example of a click bait site using Q to try to make a buck. No sense leaving it up for more than an hour and driving more traffic to them.
See simple is sometimes right, RIGHT?
Simply so!
A "Q" in the fire service means a QUINT.
An engine with a pump, tank, and hose-bed is a "Triple Combination Pumper"
A triple combination pumper that has a full complement of ground ladders (straight and extension ladders) is called a QUAD, or sometimes a "city service ladder" but has mechanical NO aerial device affixed to the vehicle.
A QUINT has a pump, a tank, a hose bed, a full complement of ground ladders, and an aerial ladder device affixed to the vehicle.
What you saw in that Getty picture was a QUINT, hence the Q in the lettering.
The Federal Q is THE siren used by Firefighters everywhere, it is the Standard. Look it up.