8 photos of the S-400 in Syria, Russia's most advanced missile defense system that the US could go up against
The photos below are of S-400 systems getting unloaded and set up at Russia's Hmeimim Air Base in Syria in 2015.
https://www.businessinsider.com/russia-s-400-missile-defense-system-sold-to-us-allies-2017-10
Yep, those are publicity photos for the systems set up to protect Russian aircraft and personnel, they are always manned by Russian Military personnel, and they are not available to defend Syrian Military or assets, theoretically to avoid conflicts with Western Troops in Syria.
The S300 systems now being deployed will also be manned by Russian Military personnel, but will defend Syrian Military and assets, thus targeting them will involve targeting Russian Military Personnel.
That's the rub.