How to Optimize Website Images for SEO

When it comes to images, many Website owners don’t realize that search engine spiders (robots that crawl the Web and gather information for search engines) can’t actually SEE the pictures on your site. In fact, search engines have no idea what a picture is unless you tell them what it is. To help search engine spiders SEE your images, you need to practice a technique called “image optimization.” So how do you go about optimizing images for SEO, and is image optimization really necessary? Read on for the answers to those questions.

Why Image Optimization Matters

With the introduction of Universal Search in 2007, Google began blending news, video, shopping and local listings into the traditional text results to create a better user experience. Images were also integrated into the Universal Search Engine Results Pages (SERPs) as well. To demonstrate this, I ran a search query for “German Shepherds” and here are the results.

SEO image optimization


There are two key elements worth noting about these blended results:

  • Prevalence of images: This particular result contains seven different images, demonstrating the growing trend of a higher ratio of images to text results in the Google SERPs
  • Image prominence: The placement of the images is also important; they live above the fold and occupy the top spot, so they are seen immediately by users

Now, whether you know it or not, many searchers click on images in the blended SERPs. So the reason for optimizing your website images for SEO should be pretty clear by now. Image optimization greatly increases the chances that Google will integrate your pictures into the search results and rank them highly.

In addition to the Universal SERPs, a large percentage of searchers also use Google’s image search function to find pictures and discover image content. According to study by, about 10 percent of Google’s visitors use the image search page.

So having your website images displayed prominently and frequently in the search results gives you the opportunity to get more clicks and drive more traffic to your website.

How to Optimize Images for SEO

As I mentioned earlier, search engines don’t have eyes, so they can’t see images and interpret their visual aspects. What they do see (and crawl) is text, specifically the HTML code of your website. So to aid search engines in identifying your images, you need to tell them what they are through image optimization methods. Here are six tips to help you effectively optimize your website images for SEO.

1) Use keywords in your image file name – When adding images to your website, make sure to name the files with keywords that describe the image. For example, let’s look at the first picture in the “German Shepherd” query for example. The file name of the image is: “” Having the keywords in the image file name tells the engines what the picture is, which helps in display in the SERPs. It may also make sense for site owners to go back and rename any existing images on their websites as well. Now, if you’re unsure of which keywords to optimize for, you can use a free keyword tool to find relevant keywords to target for your website and images.

2) Use keywords in the image alternative text (ALT attribute) – ALT text is often overlooked by many site owners, but it’s critical to getting images to rank. ALT text should quickly summarize the image and contain keywords. For example, the ALT text of the first German Shepherd picture could read “cute German Shepherd puppy.” The HTML code for the ALT attribute is <img alt=”…”>. If you’re not familiar with code and use a blogging platform like WordPress, there are a number of helpful plugins, like SEO-Friendly Images, which let you automatically add ALT text to images without having to access the HTML code.

3) Use keywords in the text surrounding the image, i.e. the image caption – Another piece of image text that gets ignored is the image caption: a cutline or text below an image. Having a caption that contains descriptive SEO keywords is also very effective for image optimization. Again, if you use a blogging platform like WordPress, you have the option of adding captions to images on your website.

SEO image optimization for WordPress

4) Use keywords in the image title attribute – The text from an image title tag automatically appears when a user hovers their mouse over the image. The title tag acts as micro content, describing the image to the search engines. Again, the same strategy applies here: briefly explain what the image is and make certain to include keywords. The HTML code for the title attribute is <img title=”…”>. And as mentioned previously, WordPress gives bloggers and site owners the option to populate the image title tag.

5) Use only high quality images – Google representatives are on record saying that searchers prefer large, high-quality images of a high-resolution, and are much more likely to click on quality images in search results. So it’s clear that quality plays a big role in the click-ablity factor of images.

6) Link to your images with descriptive anchor text links – Although this is not a common practice, building links to your images with hyperlinked, keyword-rich anchor text is a very effective image optimization technique. For example, you could link to the image of the German Shepherd puppy with the anchor text “check out this really cute picture of my German Shepherd puppy” on a separate page of your website. This method of internal link building sends an additional signal to Google about the subject matter and relevancy of a particular image.

By implementing these image optimization tips, you will greatly improve the chances that your images show up in the search results, which can translate to greater visibility, more clicks and more traffic for your website. In addition, image optimization can give you a leg up on your competitors, who likely don’t know about or practice SEO for their pictures. So following the techniques in this article will help you take advantage of their inaction and gain a competitive advantage in your market and search vertical.