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Let me drop some statistics on you: the Google domain was registered in September 1997, and today, the most popular search engine in the world indexes close to 50 billion webpages. Out of those webpages, Google has indexed more than 1 trillion page images for its Google Image Search (as of 2013).
In case you didn’t know, images drive a lot of site traffic. Just look at the stats:
• Sixty percent of users are willing to consider search results that include an image.
• Content that contains images leads to 94 percent more views.
• More than 30 percent of users share images over the Internet.
Using search-optimized images on your webpages can give you a major advantage over your competitors. Book jackets and author images, pictures of book readings and other live events, or even a simple graph can significantly attract users and convert their visits to purchases.
But there are a few guidelines to follow when it comes to the Search Engine Optimization (SEO) of images. The average score for our participants for this SEO factor was a 2.2 (a “D” grade):
Image Size and Compression
When you have a great photograph, you want to share it with your family, friends and even strangers. But sometimes that “great” photograph can have some problems. It could be faded, too big to mail, or have “red eyes” because of the flash. Search engines can be a little picky about images, too, especially when it comes to size.
I talked a little bit about images and page load speed in a previous post. Large image files can really slow down page load speed for search engines and site visitors—a double whammy leading to lower page rankings. If you want to optimize your images for the web, consider these suggestions:
• Keep your images below 100k in size – As I said above, a large image can hamper your Search Engine Result Page (SERP) rankings. Resizing as many images as you can to under 100K can speed up search engine spiders, allowing them to crawl more of your site. Smaller image sizes also mean faster load times for users browsing your page.
The image for the book There Must Be 50 Ways to Practice Writing at WayzGoose Press is one of many over 100K in size.
Now, having one or two large images is not ideal, but it shouldn’t damage your SEO. However, our evaluation showed that more than half of the WayzGoose images were over 100K. This many large image files could cause potential slowdowns for search engine crawlers indexing the website.
• Optimize, don’t resize – Avoid letting your browser or site administrator resize your images for the page without also compressing your images to 100K or below. Resizing is just an effect: the image file size will remain the same no matter what you do to the image dimensions and slow your website load speed. Also, some file types degrade the image clarity when it is 100K or smaller. Stick to .JPG files for a majority of your images. Use .PNG for small images, such as icons. A high-resolution image may also be too much for most web browsing. At a minimum, your web designer should understand all of this and tell you, based on your website and the most common browser size of your users, what size your images should really be. For our purposes, keeping them under 100k should do the trick.
• Edit your images – If you are going to use a 100K image, it should be of good quality, balanced and sharpened. If you are unfamiliar with Adobe Photoshop or other image editing software, find someone who has strong skills in these areas to further optimize your pictures, especially images you take yourself. Get a second opinion before you post.
• Exceeding the limit – Some pictures are just going to be over 100k in size if you want to preserve the quality or the clarity. In these instances, consider featuring a thumbnail that links to the full size image on a separate page.
Naming Your Image
As I mentioned in my Structured Data Markup post, the major search engines developed schema.org because most search engines have trouble discerning the traits of your product unless you tell them what those traits are. The same is true of images. Unless you explain what the image is, using specific content, Google just sees it as an image with no context. Remember, the search engines can’t actually see what’s in your image. You can remedy this with the following naming conventions:
• File naming – When you are naming your file, be as descriptive and unique as you can be. This lets the search engine (and the user) know what the image is about. Using ISBN numbers or other non-descriptive symbols provides zero information and leads to zero link juice, resulting in lower SERP rankings. Again, you need to tell the search engine exactly what the image is of, or it will not recognize it or understand when to display it when someone searches for what is in the image.
The image for InterVarsity Press’s publication Two Steps Forward: A Story of Preserving in Hope is experiencing this issue.
The file name “http://www.ivpress.com/img/book/218h/4318.jpg” relates to the ISBN book code (ISBN-10: 0-8308-4318-3) and does not offer any information about the image or the book it belongs to. By replacing the numbers with part of the book title—“Two Steps Forward”—IV Press could provide search engines with a little context for the image. It should be noted that IV Press is good at keeping the images below the 100K mark (this one is at 41K).
• Using alt tags – An additional nudge for search engines to understand your images is the alt tag. This is content found in the page code, and describes your image fully to the search engine using more text (and context) than is found in an image title file name. The maximum size for alt tags is 125 characters, so choose your words carefully, but don’t jam your alt tags full of extraneous keywords. Google and other search engines may interpret this as spam. Alt tags are also helpful if your user’s browser cannot display the image or if they are vision-impaired and require a browser reader to understand webpage elements.
• Keep content relevant (and close-by) – If you want to give Google a few more clues as to the nature of your image (and improve your page ranking at the same time), be sure that your image relates to the rest of the content on the page. For example, if the image is of a book author, there should be text close to or surrounding that image that provides information on that author. Google will use images in the vicinity of the content on the page to inform them as to how to categorize the image. Context for content is key when it comes to images.
A Sitemap for Images
As I mentioned in my post about website architecture, organizing your website by siloing helps search engines categorize and users find your webpages more easily. So it would make sense that organizing your images would have similar benefits. By adding all your site images to specific directories and subdirectories, you create a shortcut for search engines when they try to locate your images.
Using Google Webmaster Tools/Search Console can make the creation of an image XML sitemap a bit easier. This will help Google locate your images quickly and present them in the SERPs correctly. (I’ll be talking about XML sitemaps in a future post—it’s one of the criteria we used in our rankings)
Using Images to Your Advantage
Images are more than just aesthetic and informative decorations for your website. They exist as another method for potential customers to find your books online through search engines, and must be optimized accordingly, like other page content and meta description tags. Using them correctly can open up additional opportunities for SERP rankings and social integration. So it is time to take a good look at your images and see if they are ready to be unveiled or if they need a bit more tweaking.
We will now be moving on to code validation. It’s less pretty than images, but maybe more important to your SEO than you think or what some experts will tell you.
Are your site’s images optimized for search? Let me know in the comments below.
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