Here is a bit more on what they are seeing in the pics and how it happened:

ESA has released a brand new series of images, shown above and below, documenting sparks flying – as seen by Rosetta’s OSIRIS narrow-angle camera and NAVCAM wider angle cameras on August 12 and 13 – just a few hours before the rubby ducky shaped comet reached perihelion along its 6.5-year orbit around the sun.

Frozen ices are seen blasting away from the comet in a hail of gas and dust particles as rising solar radiation heats the nucleus and fortifies the comet’s atmosphere, or coma, and its tail.

And below is a cool video on comet tails.  We look forward to finding out more on this particularly fascinating comet 67P.

thanks to universetoday.com for the great info

thanks to NASA for the pic