Andromeda_galaxy -
Crab_Nebula -
Hubble_Interacting_Galaxy_NGC_5257 -
Hubble_ultra_deep_field -
m57_the_ring_nebula -
M81_wide_Galex -
M104_ngc4594_sombrero_galaxy -
Messier_10_Hubble_WikiSky -
UGC_1810_and_UGC_1813_in_Arp_273 -
All these images come from Wikipedia / Wikimedia Commons.
Image sources