Other sources of lichen photorgraphs not included in USID Lichen Guide because of nasty url's address.
Checkout by copying the url to your browser
Great images covering lichens of North America and Europe
http://www.sharnoffphotos.com/lichens/lichens_home_index.html
A few lichens of the world
http://waynesword.palomar.edu/lichlist.htm
British and Irish lichens
http://www.britishlichens.co.uk/speciesgallery.html
http://www.lichens.ie/
Tropical lichens
http://www.tropicallichens.net/