In designing Web sites, you can't necessarily trust your intuition. Sometimes you have to consult your audience. In fact, from the user's perspective, bad graphic design can really reduce a site's usability. He doesn't do graphic design, development tools, multiple browser support, or sets of hard and fast rules for site design. He simply watches people.
Spool studies how people find information on the Web.
The number one activity on the Web is information retrieval. In part of his tutorial, Spool explained his findings on graphic design and users' success. Through research, Spool's team found that graphics neither impair nor improve users' success in finding information. Photos do matter, depending on the context. In certain cases, the image is the information.