This is an old image. Check the NASA site, they had details about it. It shows the collision or merging of two Galaxies. These are located about 450 million light-years away from Earth. Over the course of millions of years, these two spiral galaxies will eventually merge.
Below a clearer picture. It's a False color image of VV 340 (UGC 9618) made from the ACS F435W (blue) and F814W (red) data. The image is approximately 100 arcsec (68 kpc) on a side. North is up and East is to the left.
©V. Charmandarais
Also note that our Milky way will one day merge with our neighbour the Andromeda Galaxy. Even though the two galaxies are still 2.5 million light-years apart, the eventual merger of our two galaxies has, in fact, already begun.
Andromeda is travelling towards us at a speed of 113 km/s, and thus it will take approx 5 Billion years. Stars will be moved to new orbits, as dictated by the newly merged galactic center. Scientists believe that even with the Sun moving away from its current orbit, our Solar system will not be destroyed.