Google has unveiled a Sort by Subject feature for Image Search that allows users to sort photos more easily by subject and improves the general topic searches.
If you're looking for a picture of a certain bird, for example, and perhaps can't remember the exact name, rather than scrolling through a combination of every type of bird and hoping you'll find the one you're looking for, Google has come up with an algorithm to sort birds into groups, whether it's a parrot, eagle, duck, cardinal, and so on.
Google said the sort by subject algorithm is adapted from Google Similar Images and Google Image Swirl. By identifying pixel values, relationships, and patterns, Google has created connections and groups for popular image searches.
Image Search Sorting: Bing vs. Google
The Google Sort by Subject technology is, and is not, the first to market. Bing has done this to an extent already, though on a less complex scale.
In the end, both methods of sorting are close enough that most web viewers would never know the difference. So, what is the difference?
Using the [london] search example, Bing includes search query suggestions at the top of the image search results pages, such as Tower of London, London Underground, and London Bridge. Google also offers related search suggestions of London Eye, London at Night, London Flag, Big Ben, and others.
On Bing, you can easily modify your query by clicking on any of their search suggestions and see your desired images. Sure, all the groups are not showing thumbnails on a landing page, but you can navigate through fairly easily. On some searches, Bing will also serve more related searches in the left navigation (e.g., "Related Animals" for a bird search).
Google's new Sort by Subject is located on the left navigation, under Sort by Relevance. The big difference is, if you don't know the name of what you're looking for but know what it looks like, Google's feature may just do the trick. Google's Sort by Subject seems to be limited to 15 choices, with no option for additional pages.
How to Use Sort By Subject for Image SEO Visibility
First and foremost, figure out what subjects Google is using for your niche. Niches like golf, fish oil, dogs, dog training, and other popular queries return multiple subject groups.
Here again, as with traditional organic web search, we can view total number of images ranking, but that figure isn't very representative of the level of competition.
The image ranking algorithm is much more difficult to reverse engineer because you can't use third-party tools to view things like citations/references and links. The best thing to do until more research has been gathered is to stick to best practices for Image Optimization. Bill Slawski has also analyzed the Microsoft Patent for Image Rankings (thanks to @mongoosemetrics for sharing this oldie-but-goodie hyperlink).
Best Practices for Ranking for Image Subjects
Here are four quick image SEO tips:
- Use the subject name in the file name.
- Surrounding copy (or text) should also be relevant to the subject name.
- Get more sites to use your image (be sure to allow time for Google to index yours as the original source of the image to receive the top ranking).
- Google isn't shutting this off for brands. If you query [hotels] you will see the big brands as their own groups. Perhaps this means brands could rank with enough buzz around the web.
One thing is for certain, with the ability to sort by subject, there are new opportunities to have an image ranked consistently beyond users corralled by auto-complete. You just have to remember you have auto-complete suggestion keywords as well as image groups to try to rank your image for!