The "missing flag image" was most likely the postcards manufacturers way to copyright their card and easily identity if another card maker abused their copyright. It's a attic that mapmakers have used for years; they add, subtract, move, have intentional typos on streets, towns rivers, streams -- anything that can be easily and quickly identified.
I can't believe it...... the first one is a painting or an coloured picture, and the second one an actual photo, this is why the difference. The wave made by the ship is not even the same, especially in the front of the ship. Laso the flag mat as reinforcement wires and is shorter in the post card