> Not on the same magnitude of cost but each time there's a new president, portraits in military installations and government offices are updated.
Chain-of-command portraits serve a practical, if minor, function; yes, more of them change when a chief executive changes than anyone else, but they also change when a batallion commander or civilian agency director changes, for the same reason as for a chief executive.
Heraldry of the monarch also serve a function, I suppose, but it is less like a chain of command photograph and more like the US national coat of arms (or the Great Seal, which has the former on the obverse); neither of which has changed substantially (there have been some rendering tweaks) since adopted by the Congress under the Articles of Confederation in 1782.