NASA Photo Galery - an extensive library of images from 10 NASA centers.  It's very cool!  I highly recommend checking it out.  Hubble Space Telescope Public Pictures - absolutely fantastic pictures of deep space objects taken by the most expensive "camera" ever made.  Even if you are not interested in space you will enjoy these photos.  Please take a look.  NOAA Photo Library - thousands of weather, oceanographic and marine species pictures.  California Museum of Photography - is a department of the University of California, Riverside.  It is concerned with the intersection of photography, new imaging media and society.  The site also has some of Ansel Adam's work.  PhotoServe - a diverse gallery of pictures from professional photographers.  George Eastman House - a tribute to the ". . . art, technology and impact of photography and motion pictures over 150 years."  SierraVisions - a site dedicated to the beauty and wonder of Califonia's magnificent Sierra Nevada mountains.  TerraGalleria - 660 photos taken in 47 National Parks and related areas.  Kerman Photo History - A Past & Present Photographic Tour of Kerman, California.  Field and Forest - an active virtual community with members located in more than 40 countries who regularly look to Field and Forest as a place of inspiration or practical information.  Lots of original work with nature as the focus. Cambridge In Colour - images from in and around the University of Cambridge in the United Kingdom.  Has good tutorials.