I am a lover of photography, especially of those most exquisite images produced by Hubble and the folks at STScI. I'm pleased to be able to offer products here that feature the haunting phenomena of deep space.
Through news releases at HubbleSite.org and the Spitzer image bank, I acquire high-resolution public domain images created by these great space observatories. I will always note the appropriate image credits on the product pages, along with information about the astronomical objects pictured.
Have you ever wondered about the amazing colors in Hubble images? In fact, only some of the images show us the nebulae or galaxies as we would see them if we were there. In order to better see and understand the composition of nebulae and galaxies, many of the exposures are made to capture a particular range of light, some of them in ultraviolet, some in infrared, and some in visible light. The Hubble's cameras take exposures in black and white, and the folks at STScI assign a color to each of the different light ranges, so that we can see the infrared or ultraviolet light in the final composite image. They explain this (and the reason for doing it) better, and with illustrations, at HubbleSite.org. Check it out, it's pretty interesting!
If you're interested in finding more deep space images, you can sign up for news releases (including the images) at that site as well, and there are a few other space telescopes worth looking in on for their images. NOAO (e.g., the Kitt Peak Observatory) make plenty of impressive images of their own, though they do claim copyright - so browse their images to your heart's content, but I can't offer them here and you should check their copyright notice before downloading or printing any of them.