NASA has huge databases of photos, some numbering in the hundreds of thousands to millions. Most of them have been archived as-is for four good reasons. Archiving the images as-is preserves the historical quality of the images. The job of cataloguing and digitizing in various sizes and file formats is in itself a monumental task. Adjusting images can sometimes be rather subjective. Space is dark.

Ultimately many of the images of space exploration which can not be taken from ground based locations originate from NASA as a main source. For those who may be unfamiliar with the many locations NASA websites, we have listed a few here. This list is not intended to be exhaustive. From time to time new locations may be added or changes may be made.

Planets and Solar System

Current Solar Images: A collection from international spacecraft observing the Sun.
http://umbra.gsfc.nasa.gov/images/latest.html

Photographic highlights from recent missions
http://eol.jsc.nasa.gov/debrief/
"These photos include images selected by astronaut crews, our scientists, and collaborators. These photographs were chosen based on criteria such as the scientific information contained in the image, illustration of important dynamic events, geographical interest, and aesthetic values."

Welcome to the Planets - A collection of many of the best images from NASA's planetary exploration program. Geared toward educators.
http://pds.jpl.nasa.gov/planets/

Planetary Data System Imaging Node: PDS:
"You want pictures of the planets? This is where they'll be..."
The Imaging Node of the Planetary Data System, PDS, is, "the curator of NASA's primary digital image collections from past, present, and future planetary missions. The node provides to the NASA planetary science community the digital image archives, necessary ancillary datasets, software tools, and technical expertise necessary to fully utilize the vast collection of digital planetary imagery."
http://www-pdsimage.jpl.nasa.gov/PDS/

NASA's Planetary Photojournal - high quality, press released images
http://photojournal.jpl.nasa.gov/

PDS Map-A-Planet - custom image maps of Mars, Earth's Moon, Venus, and Jupiter's Moon Callisto
http://pdsmaps.wr.usgs.gov/maps.html

Planetary Image Atlas- science data from CLEM, GLL, MGN, MGS, MPF, VL, and VO missions.
http://www-pdsimage.jpl.nasa.gov/PDS/public/Atlas/Atlas.html

Astro-Science

Earth from Space
http://earth.jsc.nasa.gov/mm.html

Cities collection
http://eol.jsc.nasa.gov/cities/
Here you can look up your favorite city on our list and display digital images for some of the best photographs, selected outstanding photos of cities around the world

Earth Science Pictures, has a huge byte size main page. It is huge. Unbelievably huge. It's the biggest web page we have ever seen. We downloaded 3.6 Mb and would have given up but, the page was a focus of lots of great material. There were about 100 images. As just one example, there was a 536 Kb gif animation which really didn't show much and which should have been just a thumb image link to another website or page.

http://pao.gsfc.nasa.gov/gsfc/earth/pictures/earthpic.htm

Space Science Pictures:
Press Release imagery from the Goddard Space Flight Center.
http://pao.gsfc.nasa.gov/gsfc/spacesci/pictures/spacepic.htm

Images of environmental change from the U.S. Geological Survey.
http://edcwww.cr.usgs.gov/earthshots/slow/tableofcontents

Nasa Photo gallery
http://WWW.HQ.NASA.GOV/office/pao/Library/photo.html

The Space Shuttle Web Archive has photos from mission STS-71 (June 1995) on
http://shuttle.nasa.gov/

OZONE Images and animation from NASA's Total Ozone Mapping Spectrometers, TOMS, the instruments that brought us the first space views of the Antarctic Ozone Hole.
http://jwocky.gsfc.nasa.gov/multi/multi.html

General-use images of phytoplankton concentrations from Nimbus-7's Coastal zone Color Scanner.
Some images have been combined with land-surface data to create images of " The Living Earth."
http://seawifs.gsfc.nasa.gov/SEAWIFS/IMAGES/GALLERY.html

Vegetation - A research archive of images from the Advanced Very High-Resolution Radiometer showing changes in vegetation across the Earth's land surface
http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/BRS_SRVR/avhrrbrs_main.html

Earth Observing System Educators' Visual Materials:
A variety of remote-sensing images comprising a collection for teachers' use
http://eospso.gsfc.nasa.gov/eos_edu.pack/toc.html

STSCI Public Release Images
http://www.stsci.edu/EPA/Pictures.html

Vehicles, Robotics, Machines

Resources for educators
http://pao.gsfc.nasa.gov/gsfc/educ/trl/res.html

Kennedy Space Center Shuttle Countdown Image Archive
http://www.ksc.nasa.gov/shuttle/photos/

Space Shuttle photo archive
http://spaceflight.nasa.gov/gallery/index.html

International Space Station photo archive
http://spaceflight.nasa.gov/gallery/index.html

Spacewalk Helper/Retriever
http://tommy.jsc.nasa.gov/er/er4/evahr/

Reusable LaunchVehicle Program - A concept space vehicle for the future.
http://stp.msfc.nasa.gov/

NASA Telerobotics Photo Archive: Images of planetary rovers, on-orbit systems, new technologies, end effectors and terrestrial applications.
http://ranier.oact.hq.nasa.gov/telerobotics_page/photos.html