It's worth remembering if you're ever designing or selecting an image for a stamp that sooner or later that image will be scrutinised by philatelists, who are not known for lacking attention to detail.

Recently the US Postal Service has had to acknowledge a somewhat embarrassing mistake: the image of Lady Liberty from the famed statue is no such thing, but an image from a knock-off version located in Las Vegas.

The error was spotted by Linn's Stamp News and subsequently reported by Reuters. The photo used on the stamp shows a rectangular patch on the crown that is present on the 14-year-old statue at the New York-New York Hotel and Casino in Las Vegas, Nevada, but not on the 305ft (93m) copper statue in New York.

Other clues are that it is holding a cocktail aloft and has its other arm around a new husband. (Actually we're waiting for confirmation on that.)

The stamps are expected to remain in circulation on mass however, which means it's unlikely that they will become especially valuable any time soon. In that respect they are similar to the Hawai'i apostrophe stamps rather than any of the famous inverts and investment-grade overprints such as the Cayman Islands double print.