Like most entrepreneurs, Frederick Hutson cannot resist trying to solve a thorny problem. His company, Pigeonly, based in Las Vegas, taps an underserved and “captive” market by offering prison inmates an easy and efficient way to receive photos from loved ones and to make phone calls to them inexpensively. “Isolation is the worst thing for an inmate,” Mr. Hutson said. “It makes it hard for him to rebuild his life when he gets out.”

Hoping to reduce recidivism, he came up with an idea for an online platform, called Fotopigeon, that lets friends and relatives upload photos, which are then sent through the postal service directly to the incarcerated for a flat fee of 50 cents a print. “Companies like Shutterfly and Snapfish — their packaging won’t get accepted by prisons,” Mr. Hutson said, “because they don’t like anything that doesn’t come in a plain white envelope.”

Mr. Hutson knows his market well. In October 2007, when he was 24, he was deeply immersed in solving a different business problem — the inefficient distribution of marijuana from Mexico to Florida — when 10 Drug Enforcement Agency officers showed up at his mail store in Las Vegas with guns drawn. Mr. Hutson had been moving marijuana through his business, using DHL, UPS and FedEx trucks to transport it to Florida. With no previous criminal record and an honorable discharge from the Air Force, which he entered directly after graduating from high school, Mr. Hutson expected to get off with a “slap on the wrist.” Instead, he was sentenced to 51 months in prison.

Like many former inmates, Mr. Hutson, now 29, has benefited from a growing number of support programs available to those who want to start businesses. In Manhattan, for example, Catherine Hoke founded Defy Ventures, a nonprofit organization whose participants have started 44 businesses, including an event-planning company, a cleaning service and a mobile barbershop. “One of the primary skills they need to survive on the street are good hustling and sales skills,” Ms. Hoke said. “I’m not saying that all drug dealers make great entrepreneurs, but many of the skill sets are shared.”