Alt text is used to help computers read images.
But can alt tags affect your organic search rankings?
Read on to learn whether there is any connection between alt text and improved rankings in Google Image Search results.
The Claim: Alt Text Is A Ranking Factor
What is alt text?
Alt text is an HTML image attribute. It allows you to create an alternative text version of your image if it cannot load or has an accessibility issue.
Because of its importance to Google Image Search, it is considered a ranking factor.
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Alt Text As A Ranking Factor: The Evidence
Google emphasizes how alt text plays a vital role in getting your images recognized by Google Image Search.
You will find a page on image best practices in Google Search Central’s Advanced SEO documentation. In a section called “about alt text,” Google discusses the use of alt text.
“Google uses alt text along with computer vision algorithms and the contents of the page to understand the subject matter of the image. Also, alt text in images is useful as anchor text if you decide to use an image as a link.”
While the company doesn’t specify that alt text will improve your rankings, it warns website owners that improper use can harm your website.
“When writing alt text, focus on creating useful, information-rich content that uses keywords appropriately and is in context of the content of the page.
Avoid filling alt attributes with keywords (also known as keyword stuffing) as it results in a negative user experience and may cause your site to be seen as spam.”
It also offers the following examples of good and bad alt text usage.
Google Sites Help documentation indicates that images may come with pre-populated alt text, including keywords for which you may not want to optimize.
“Some images automatically include alt text, so it’s a good idea to check that the alt text is what you want.”
For example, when I download stock photos, a text description of the image is embedded in the file.
Screenshot by author, August 2023When uploaded to a content management system (CMS) like WordPress, the text descriptions may need to be moved to the alt text field or modified to remove unnecessary keywords.
Screenshot from WordPress, August 2023In Google Search Central’s “Search Engine Optimization Starter Guide,” it offers the following advice about alt tags when using images as links:
“…if you’re using an image as a link, the alt text for that image will be treated similarly to the anchor text of a text link. However, we don’t recommend using too many images for links in your site’s navigation when text links could serve the same purpose.”
In 2020, John Mueller, Google Search Advocate, answered a question about the alt text of a quote image during a Google Webmaster Office Hours. In the answer, he talked about how Google uses it:
“For Search, what happens with the alt attribute is we use that to better understand the images themselves, in particular, for Image Search. So if you didn’t care about Image Search, then from a Search point of view, you don’t really need to worry about alt text.
But if you do want these images to be shown in Image Search, which sometimes it makes sense to show fancy quotes in Image Search as well, then using the alt attribute is a good way to tell us this is on that image and we’ll get extra information from around your page with regard to how we can rank that landing page.”
Moz mentions ranking factors about alt text. Instead of saying that the alt text itself is a ranking factor, Moz advises:
“…alt text offers you another opportunity to include your target keyword. With on-page keyword usage still pulling weight as a search engine ranking factor, it’s in your best interest to create alt text that both describes the image and, if possible, includes a keyword or keyword phrase you’re targeting.”
In 2021, during a Twitter discussion about ALT text having a benefit on SEO, Google Developer Martin Splitt said:
“Yep, alt text is important for SEO too!”
Later in 2021, Mueller noted that alt text is not magic during a conversation about optimization for indexing purposes.
“My understanding was that alt attributes are required for HTML5 validation, so if you can’t use them with your platform, that sounds like a bug. That said, alt text isn’t a magic SEO bullet.”
[Recommended Read] → Ranking Factors: Systems, Signals, and Page Experience
Alt Text As A Ranking Factor: Our Verdict
Alt text is a confirmed ranking factor for image search only. You should craft descriptive, non-spammy alt text to help your images appear in Google Image Search results.
Alt text is definitely not a ranking factor in Google Search. Google has clarified that alt text acts like normal page text in overall search. So it’s not useless, but it’s not a separately considered ranking factor in your page content.
That doesn’t mean you should ignore alt text. It’s a helpful accessibility tool for screen readers. When you’re writing alt text, ask yourself what you want someone who can’t see the image to understand about it.
Featured Image: Paulo Bobita/SearchEngineJournal
