The Space Telescope Science Institute has released the second-largest ever image of a galaxy, a 16000 x 12000 pixel composite of the M101 (Pinwheel) Galaxy, taken by Hubble over a period of 51 exposures (the largest was a 21904 x 14454 pixel mosaic of M31 composited by Rob Gendler). The images in various sizes (including the 455405 kb original) can be downloaded here. I downloaded the 10 Meg version and selected a few smaller sections of the image, reproduced below.
The whole galaxy; the original image has roughly 27x25 pixels for every pixel in the image below
A closeup of the core. The lacy structures are probably interstellar dust backlit by the core
An image of the inner part of one of the arms, again with lots of dust silhouetted by the bright stars behind
The following two images are of arms further out from the core; note that there are even more distant galaxies visible, shining through the arms of M101
Technorati Tags: Space, Hubble, Galaxy