A few weeks ago I wrote about my reasons for choosing an image of the volcanic plumes on Io as one of my banner images. The NASA New Horizons mission to Pluto and the Kuiper belt has captured the first movie of one of these plumes. The five images that make up the movie clearly show the motion of material in the plume from the Tvashtar volcano, and the slow rotation of the satellite. I can see one other plume at the 7 o'clock position from Masubi. NASA's site says there's another faint plume at 10 o'clock, but I cannot see it.
Image credit: NASA/Johns Hopkins University Applied Physics
Laboratory/Southwest Research Institute
Tvashtar in Motion