Help Search Engines Find Your Photos
Search engines have a problem with image files. They cant see them. To a search engine, your photograph is just a file name, unless you add more information to help it analyze where it should fit in the search index. If your image isn't properly indexed, it won't appear in relevant queries on a search engine. Fortunately, you can help overcome that problem.
Use a Relevant File Name
It may seem like an obvious thing to do, but many people overlook this step. If you upload a file named “image.jpg” or dscn4231.jpg”, the search engine dutifully indexes and categorizes it using that text. While writing this little tidbit, I did a search on images.google.com for image.jpg. Google's response? About 3,670,000,000 results.
If you want someone to find your photo of the Eiffel Tower in that mess, good luck. Why not help the search engine by naming your photo with something relevant to its content?
Use the ALT Attribute
There's an attribute of the HTML IMG tag called “alt” and it provides a useful service. It allows you to associate text with your image. You can consider it part of making your site more accessible. For people who use screen readers, the text in the “alt” attribute lets a person who can't see your image at least know what it is. Another purpose is to display a message when the cursor stops over an image. The text in the “alt” attribute also acts as anchor text, giving the search engine something it understands and can use to index your image.
I like to use creative titles for my photographs, but those titles aren't very descriptive for someone performing a search. Fortunately, I can use the title I want and include “alt” text that's more relevant for search or screen readers. Take a look at this example from the WordPress Image Uploader.
The Title is the creative name I want to use, but the Alternative Text field includes the information a search engine will use. The description helps me later when I want to search for the photo in WordPress, but it isn't included in the HTML of the web site.
Simplify Your File Structure
Consider consolidating all of your images in the same folder, rather than spreading them all over the place. When a search engine knows about that folder, it can examine all of its contents. If you have multiple folders containing your images, the search engine may find some folders and miss others.
Use an Image Sitemap
Sometimes, you may have a valid reason for keeping your images in separate folders. WordPress has a tendency to put images in different folders for each month of the year (subject to how you configure the software). If you've been blogging for a few years, it would be quite a task to move all of those images and update the HTML in the posts that refer to them. Fortunately, there's another alternative.
Google defined a specification for image sitemaps. It's an XML file that describes the location of each of your images. If you use WordPress, you can find plugins that easily create an image sitemap file (there are other formats for your blog, video, etc.). Once your sitemap exists on your web URL, you can inform Google and other search engines by their webmaster tools to upload the sitemap. It may take a few days for the search engine to crawl all of your images, but now it knows they exist.
Simple Steps – Big Results
When you upload your images, paying attention to those details will help people find your images using Google, Yahoo, Bing and other search engines. What if you have a lot of images uploaded? Then you have a decision to make. Do you want to go back and replace those images with file names that make sense? Whether you do that or not, you can at least add some descriptive text in the “alt” attribute and create an image sitemap. That's what I'm doing.