All images require text equivalents but "alt" text must also meet certain criteria otherwise it may be considered suspicious. For example, using placeholder text (i.e. alt="image goes here") in place of an actual text equivalent is considered unacceptable.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd"> <html lang="en"> <head> <title>aert1.0/1.1.1</title> </head> <body> <img src="animage.gif" alt="{short description of image}"/> </body> </html>
W3C WAI: http://www.w3.org/WAI//
HTML Techniques for WAI 1.0: http://www.w3.org/TR/WCAG10-HTML-TECHS/