I believe it shows a very truncated version of this historical event : "The Eagle of the French 45th Ligne captured by the Royal Scots Greys, during the famous charge of the Scots Greys at Waterloo (1815). The kilted figures carrying muskets are the 92nd Highlanders." You can find many examples of popular paintings if you google "battle of waterloo" "royal scots greys" "capturing the eagle". The uniform details of the the 2 regiments are reasonably accurate as is the depiction of the Eagle. I would assume because of space restrictions the horse/s (which were integral to the event) were omitted. It fits with the idea of "Victory" being achieved when the standard of the enemy was captured.
