I was asked recently whether GazoPa includes advertisement. We have not included advertisement in any forms such as text or display ads. But an advertisement is one of major monetizing method, so we'll consider to include advertisements.
Google did trials to include advertisement in their image search and 'trials showed that text ads drove people away from conducting image searches, and Google dropped that idea' in 2006. But as far as I know, Google started including text advertisement into image search last year. It means they think users' behaviors have changed and they accept advertisement on image search. Advertisements are located on upper side of search results and I have never seen it is posted at the right side of search results as in web search.
Yahoo image also includes advertisement as well, but advertisement are located at the right side of search results. Bing has not included advertisement at their image search.
Google experimented display ads in 2008. But I have never seen them and Google might have not come to final decision yet. Although there are no major search engines who include display ads, display ads should be next trend, because this type of ads can attract more users than text ads. We can see display ads at Cooliris and these ads are inserted into images very naturally (Actually, these are video ads.). Questions are how relevant display ads can be. Our similar search technology can solve this relevancy issue, so I think we can show display ads naturally at GazoPa.com.