Shares of Santa Monica-based online postage vendor Stamps.com Inc. surged 20 percent last week after the company announced its popular PhotoStamps program was set to return to the market.

A test run of the personalized stamp service, which allowed customers to create official U.S. stamps from their own pictures, was halted last September after images of Unabomber Theodore Kaczynski and other notorious figures made their way through screeners.

Since then, Stamps.com has hired personnel with “expertise in world history and world culture,” said Chief Executive Ken McBride. The company also beefed up its database of thousands of images deemed inappropriate for postal stamping to try and avoid its former gaffes like stamps of Monica Lewinsky and presidential whistleblower Linda Tripp.

Last week, the company began taking orders and said it expects PhotoStamps to be available under authorization of the U.S. Postal Service beginning May 17 for a yearlong market test.

It also raised its revenue forecast for the year to $56 million from a previous forecast of $48.6 million. McBride said about $5 million of the increase was due to the new launch of the PhotoStamps program.

Stamps.com had already rebounded from last summer’s setback by targeting business customers with other online postage products. It reported first-quarter net income of $1.6 million, compared with a net loss of $4.5 million for the like period a year earlier. Revenues rose to $11.8 million from $7.6 million.