My memory was inaccurate.
Assuming the soldier is 5-6, the poster is somewhere between 12' and 15' wide (there's a parallax distortion between the top and the bottom). The length, though it doesn't appear to be fully unrolled, would be somewhere between 30' and 37'.
In other words, that's a painted bulletin sized piece of Tyvek -- requiring an even larger ink jet printer.
Can you tell if it's been pieced? I know the billboard banners are done in sections. If so, then you wouldn't need a printer that would put out a 14+ width banner, right?