Facts and Opinion About Fahrner Image Replacement
http://www.alistapart.com/articles/fir/

Clark, Joe
List Apart, A
2003

Abstract:

Fahrner Image Replacement and its analogues aim to combine the benefits of high design with the requirements of accessibility. But how well do these methods really work? Accessibility expert Joe Clark digs up much-needed empirical data on how FIR works (and doesn’t) in leading screen readers.