Does Alt Text Impact Google Image Search Rankings?

The primary purpose of alt text for images is to make websites more accessible for people using screen readers and assistive technology. But can it also be used to improve SEO and search rankings?

Accessibility is a key aspect of Google's mission to “make a better web.” The world’s most popular search engine says it is committed to accessibility and that “Everyone should be able to access and enjoy the web.”

When awarding a high ranking, Google wants to ensure that you are authentic, that your site is secure, that you have high-quality, relevant content for searchers, and that your website is fast and easy to access, understand and navigate for those of all abilities. The goal is to ensure that all users can easily find and access the information they want and that their online experience is positive.

Alt text, or alternative text, explains visual images in the context of the web pages where they appear. The text is read out loud to people using screen readers. When there is no alt text, screen reader users just hear "image."

The impact of image alt text goes beyond meeting accessibility expectations. It also helps search engine crawlers understand an image’s subject matter so they can produce better, more accurate and relevant search results for users.

But does alt text improve organic search rankings? To answer that question, it is useful to understand alt text and how it relates to Google image search results.

What is alt text?

Alt text, also known as alt attributes or alt descriptions, is an element of HTML code. It is used to describe what an image on a web page looks like and/or does. Alt text appears in place of an image that does not load or has accessibility issues and is indexed by search engines to better understand an image and the content on the page it's on.

Does alt text impact Google image search?

In a word, yes. However, Google doesn’t explicitly say it is a ranking factor for its image search rankings. That said, from an SEO perspective, if it's important for your brand to rank high in Google image search results, adding alt text to images can improve your ranking.

Here’s what Google has to say about 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.

“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.”

This is important: Google is laser focused on creating a positive user experience for all and while it points to the value alt text can bring in this regard, it will penalize sites that misuse it. To this end, it provides the following examples of bad and good alt text in the description of a photo of a puppy:

• Bad (missing alt text): <img src= “puppy.jpg”
• Bad (keyword stuffing): <img src=puppy.jpg” alt= “puppy dog baby dog pup pups puppies doggies pups litter puppies dog retriever labrador wolfhound setter pointer puppy jack russell terrier puppies dog food cheap dogfood puppy food”/>
• Best: <img src=”puppy.jpg” alt= “Dalmatian puppy playing fetch”/>

Alt text should always be short, clear and concise. Aim for between 100 and 200 characters. Where possible use full words – avoid acronyms and symbols – and include your target keyword or key phrase. Some images, such as stock images, automatically include alt text. If the alt text isn’t what you want to see, Google recommends changing it to better meet your needs.

Also note that while alt text is important to rank high in Google image searches, implementing alt text is not a ranking factor for general web searches. When it comes to web search, Google’s algorithms process alt text as typical on-page text – not an enhancement to accessibility or overall user experience.

Tip: Alt text to describe purely a decorative image that does not provide context for content on a web page likely won’t improve accessibility or impact SEO.

To learn more about Google’s views on image SEO visit Google Search Central, which provides a list of best practices.

Alt text helps computers read images and makes these images understandable to people using screen readers and other assistive technology. It’s a critical tool for improving web accessibility and your ranking in Google image searches.