“This image, captured with the NASA/ESA Hubble Space Telescope, is the largest and sharpest image ever taken of the Andromeda galaxy — otherwise known as M31.This is a cropped version of the full image and has 1.5 billion pixels. You would need more than 600 HD television screens to display the whole image.”
via Sharpest ever view of the Andromeda Galaxy | ESA/Hubble.
I had to download the 4.3 GB file. For science.