Unlike many - if not most - other branches of science, astronomy is in the very fortunate position to provide beautiful images almost effortlessly. Point your telescope at almost any position in the sky, and out pops something spectacular. In fact, you can even point your telescope at a spot where seemingly isn’t much going on, and you get one of the most important cosmological images ever made (even though for laypersons, this particular image looks a bit boring). The folks at the Space Telescope Science Institute know this very well, of course, so every week or so, they release some new eye candy. The Hubble Space Telescope gallery is well worth the visit - just check out the Sombrero Galaxy in full resolution. I’d also recommend looking through ESO’s image archives - have a look at, say, the radio galaxy Centaurus A. For those more interested in pretty pictures from the solar system both the Galileo and Cassini-Huygens space mission image galleries hold a plethora of amazing images.