The London "Daily News" (May 1, 1875) reports, as part of "The Royal Academy exhibition," a painting by H. S. Marks:

"'The Three Jolly Post-Boys,' a bright, merry, vivacious picture of three blue-jacketed post-boys sitting outside an ale-house, and entertaining the servant-maid not a little by their ways and humours. They are the three thus described:

    Three jolly post-boys
      Sitting at the Dragon                                                                                       
    Three jolly post-boys
      Sitting at the Dragon,
    And they determin-ed,
    And they determin-ed,
    And they determin-ed
    To finish out the flagon.

Let us hope it was not so much after all - among three."

You can buy a second-hand framed sepia print on eBay:

https://www.ebay.com/itm/325269432016

One of the "boys" looks to be about sixty.

"Punch" published a take-off in 1888 featuring three jolly politicians:

https://photos.com/featured/three-jolly-post-boys-1888-artist-print-collector.html