xcavator.net launched earlier this week on the back of parent company CogniSign's image recognition technology. For now the site only searches iStockPhoto (royalty free) and Photovault (rights managed), so it is really more like a replacement search engine for those two sites than a full on stock photo search. Even so, the technology is unique and impressive.

Searches can be made by keyword, or by color -- or a both at the same time, and photos that catch your eye can be dragged into a special area to save them while you search. The keyword search didn't work any better than the search found on iStockPhoto's or Photovault's websites, in my opinion. But the addition of the color search is very helpful. xcavator.net also has a utility that lets you upload a photo and match the colors from it. As they add more sources to their search engine, the usefulness of xcavator.net will improve.

Features: A
Search Results: B

Yotophoto searches only free stock images (free as in no cost). That means it indexes images from sites like MorgueFile, stock.xchange, Flickr, and Wikipedia. I thought that because Yotophoto only searches free sites the results might be limited, but I was wrong. It turns out there are a lot of free use images out there on the web! The difference is that you have to do some digging to weed out the poorly shot photos from the good ones.

Yotophoto offers some neat search features beyond the standard keyword search. You can also specify a color to search for, as well size, and orientation (landscape, portrait, or square), and can even narrow by license (creative commons, GNU FDL, public domain, or site specific).

Features: A
Search Results: B+

Like Yotophoto, everystockphoto searches free to use images (specifically those licensed under a creative commons license). They claim to index 1,042,822 free photos, and search a lot of the same sites as Yotophoto. Even so, I generally got different results for the same keyword search on each site.

Though it doesn't have many advanced photo searching features, once you join the site (free) you can tag and save your favorite photos for easy location later. Searches also load secondary results from for pay stock site Fotolia.

Features: C+
Search Results: B

PicFindr is another relatively new stock image search engine that searches only free use images (sort of -- it also searches for pay images from Dreamstime, if you ask it to). According to the site, PicFindr is "not alpha - not beta - just not done yet." It seems to search five sites (stock.xchang, ImageAfter, Dreamstime, and two others I could never get to respond), and it loads image results in boxes for each site. PicFindr uses Flash to display results and doesn't offer much in the way of special features (though a "favorites" feature is supposedly coming soon). One special feature it does have is a Firefox 2 search bar plugin, which is convenient for Firefox users.

Features: C
Search Results: C+

Fotosearch searches over 2 million images from over 100 traditional, for pay stock photo, illustration, audio and video providers, including the big names like Corbis and Comstock. It mainly offers a simple keyword search, but lets you narrow your search within specific providers, search by image type, size, license, and orientation.

I expected Fotosearch to blow away the competition, simply due to the sheer number of images it searches, but while the images it returned were generally more professionally shot than on the other sites in this round up, they weren't necessarily more complete results. (For example, Fotosearch is the only site in the round up that didn't return a single result for my query for "sock monkey.")

Features: B
Search Results: B+