It turns out that consumers rely on images in search engine result pages more than Google and Microsoft execs thought. Knowing this can help SEO professionals better optimize sites, according to executives from both companies who spoke at the Search Engine Strategies conference last week in San Jose, Calif.

It also turns out that image search is very important. Todd Schwartz, group product manager of online services division for Bing at Microsoft, shed light on the types of queries that consumers search for on Bing, he says. Following "Web search" categorized as a "vertical," images took the No. 2 spot.

Schwartz says that across the search engines, more than 1 billion queries occur monthly in the vertical, excluding blended search results that serve up organically on the page. "Search is a ubiquitous activity," he says. "It's kind of second to brushing your teeth in terms of daily activity."

People typically engage with results that return images, too. Microsoft found that people view more pages per query when accompanied by an image, and they spend more time on the page. That also includes Bing's home page, Schwartz says.

Delving deeper to determine how images influence search, Microsoft found that visual snippets combining text and images in a search session reduced the cognitive processing time, taking a person 20% less time to understand the content on the page. In the study, consumers were asked how search played a role in their everyday lives. Those who participated told Microsoft the Web search helped them make shopping-related decisions 65% of the time; travel, 45%; health, 40%; and mobile, 70%. The need for high-quality images "enhanced" the consumers' ability to process the decisions.

While 40% of the overall image queries are related to commercial searches, such as travel and shopping, Microsoft found that another 44% of the searches for images related to science and nature and fashion, as well as tattoos. The remainder of searches related to entertainment, from movies and television to video games and celebrities.

Not surprisingly, R.J. Pittman, director of product management for global search properties at Google, believes that image search as a vertical sits at No. 1, rather than No. 2. The growth comes from the "more than 1 billion" camera phones being sold yearly, and the ability to share pictures. Google sees "hundreds of millions of searches daily across billions and billions of images," he says. Images are no longer a "nice to have, but a must have" piece to promote businesses online.

Pittman says Google has begun to rank images based on the quality of the image. People need to stop thinking about the photos as images and look at them as digital bits of information, where pixels in the frame actually mean something. Google considers more than the sitemap feeds, title tags and attached metadata when ranking images. The search engine now looks at what's in the image. It helps Google find and serve up similar images through object and facial recognition, according to Pittman, who says to consider these facts to better optimize "when building next-generation Web sites."

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