ESA Astronaut Alexander Gerst is currently spending 5 and a half months living and working on the ISS for his Blue Dot mission.  The timelapse is made from a sequence of images taken once per second. Playback is at 25 frames a second, so everything you see looks 25 times faster than what the ISS crew experience. The artistic effects you see are made by superimposing images and fading them out slowly. 

[Gizmodo, ESA]