Roanoke historian Scott Crawford likes to find the hidden messages in old paintings.

That doesn’t mean he’s searching for secret codes. Rather, he studies images and ferrets out the meaning behind them that would have been apparent to viewers at the time they were painted, but might be lost on a viewer today.

His research recently prompted the National Gallery of Art in Washington, D.C., to change the name of a work in its collection. For decades, the museum referred to an 1890 oil painting by American artist Linton Park as “The Burial.” The name seemed to make sense, as the piece depicts people mourning at a grave, with a Union soldier and a man holding a shovel looking on.

Yet Crawford, 45, argued to the museum that the title didn’t fit. Based on what he deduced about what the painting depicts, he suggested it should be called “The Exhumation.”...