The image has been photoshopped. The original is a still image from a 2009 movie called A Serious Man:
About the Joy Division’s album Unknown Pleasures and pulsar CP 1919: Peter Saville did use an image of radio waves from pulsar CP 1919 in the album cover. He reversed the image from black-on-white to white-on-black and printed it on textured card for the original version of the album (source: Wikipedia).
Note that there are many fake versions of this photo.