Internet Orchid Species Encyclopedia - A comprehensive site that also gives some cultural comments for a lot of species. The photographs are not always right, so double-check.

Flickr - This is a massive searchable database of photographs uploaded for public viewing, and there are lots of orchid photographs to be found. Again, not all of them are properly identified but you can write to the owner of the photograph and get information or suggest IDs. I strongly encourage you to submit your photos here as this site can become an important tool for the exchange of orchid information!

Eric Hunt's Orchid Photographs - A bay area orchid (and other stuff) photographer. Eric photographs the local shows and meetings, and as we are species-obsessed in the Bay Area, you will find many interesting and unusual flowers documented here.

The Pleurothallid Alliance - Lynn O'Shaughnessy maintains this website for the Pleurothallid Alliance, and she catalogs photographs for many many Masdevallia, Dracula, Lepanthes, Pleurothallis, Restrepia, etc., species.

Dracula Species Database - Chad Sarles maintains this website of information on Dracula species, with many photos submitted by yours truly.

Books:

Many of the photographs in the Colombian Orchid Species volumes were photographed in the collection of my supplier, so you can be confident that they are the plants you'd be receiving. I know this series is not likely to be found in your local library; I have relatively easy access to it at the Strybing Arboretum, so I can look something up for you if you really need to know. The same thing goes for the Icones Pleurothallidinum volumes.

A good book for Masdevallia photographs is Masdevallias: Gems of the Orchid World (Gerritsen and Parsons, Timber Press, 2005). It's available on Amazon.com and well worth the purchase. Buy it!