Picture this: A customer—let’s call him James—pulls out a smartphone and snaps a photo of one of the engagement rings in your showcase. Then he starts tapping the keys on his device.What’s happening? James is showrooming: examining merchandise in a brick-and-mortar store, then using a smartphone to find the best price for the same style on the Web. He’ll walk away and order it online, making clear that he’s used your store, with its expensive overhead and security costs, as a convenient way to try the ring on for size (so to speak).Customers like James are on the rise. “With today’s technology, everyone has a smartphone on their hip,” says Jenny O. Calleri, brand ambassador for T-Bird Jewels in Las Vegas. Those smartphones are turning into powerful shopping companions.Showrooming, like technology in general, is breaking down the walls that have long blocked public acces