Hummingbird pictures are fascinating. Watching the actual flight of a hummingbird isn't easy and fine photographs can show them in a way that watching them can't.
Take a look at the book, World of the Hummingbird, a beautiful set of photographs accompanied by an interesting introductory text. Another book, The Hummingbirds of North America: A Photographic Guide, is organized as a guidebook, listing each specie with its description and habits, but also has hummingbird pictures including 200 photographs. Peterson's A Field Guide to Hummingbirds of North America is a well-regarded and convenient guide that includes 180 hummingbird pictures in color.