Ok I'm confused... that highway sign says New Orleans, but in the background that's the Palace Casino in Biloxi, MS, right at the foot of the Highway 90 bridge to Ocean Springs. The only explanation that isn't a mistake is that's meant to be a "New Orleans (x) Miles" sign from the highway. The mistake explanation is the artist based this on a real photo with the Palace in the background and didn't know where the pic was taken and just assumed that it must have been New Orleans. Which is plausible considering that most people outside the area think that's the only place the storm hit.