The pictures, taken by the New Horizons spacecraft, show the large, volcanically active moon called "lo" while an eruption is taking place, London's Daily Mail reported.
The probe's seven cameras show an umbrella-shaped plume rising 200 miles into space from the volcano Tvashtar.
"It's really exciting that it performed for us," John Spencer of the Southwest Research Institute in Boulder, Colo., told the Mail. "Galileo was orbiting for six years and we never saw plumes like that," he said, referring to an earlier mission.
The probe also revealed a mystery volcano, so young its lava has just reached Io's surface, but has yet to emit enough gas to produce a plume.
"We're seeing the birth of a new volcano here," Spencer said.