7 Best Practices for Alt Text for Images to Get a Nice SEO Boost


As with many things in life, the devil is in the details of search engine optimization.


Success in search engine optimization starts with a large, overarching strategy and decision-making, but execution depends on millions of tiny details that together have a large, cumulative effect.


Keyword-optimized blog posts published every week. Remove unused CSS and script on a web page so that it runs a few seconds faster. All of your pages should be linked to each other in a way that makes logical sense, right down to the anchor text you use for the links. Ultimately, it's small details like these that can make the difference between the success or failure of an SEO campaign.


It doesn't get much smaller than the alt text for images. The text alternatives for images and videos are something that the vast majority of internet users don't even think about, let alone see.


Most SEO laymen would understandably consider the alt-image text to be unimportant – an unimportant technical SEO issue that webmasters and marketers can easily ignore. They are wrong. Alt image text is a good opportunity for better rankings and a better user experience. If it is abused or neglected, there is a risk that the quality of your website will be compromised and the low-hanging keyword rankings will get stuck.


We explain why alt text is important, what impact it has on accessibility and usability, what benefits it offers from an SEO perspective, and what best practices to follow.


What is image alt text?


Alt text (short for alternative text) is a text replacement for non-text content, such as images and videos. It is used to describe an image on a web page, both the context of the image and what can be seen on the image itself.


Alt text, also called alt attributes or alt tags, is used to make a web page more accessible to visually impaired users who use screen readers to understand the images. They also take the place of an image if it cannot be loaded properly. Search engines also use the alt text to understand the context of an image in relation to the rest of the page.


Image alt-text is part of the HTML code of a website, and is encoded into the web page using the alt attribute (e.g. <alt="image-alt-text-example").


They are used by SEO experts as a way to place keywords and optimize images. When a search engine crawler visits a web page, they use alt text to understand what the image is for, what happens on the image, and why it's important. Therefore, the alt text is a good place to insert long-tail keywords that help the search engines understand the image and get a little SEO boost.


Why is alt text important?

Using alt text for your images is not only beneficial from an SEO perspective, but also improves the usability of your website.


The purpose of alt text of images is to make the Internet more accessible to users who cannot see images themselves. However, search engines also use them during the crawling and indexing process to "see" an image, which also brings them SEO benefits.


Alt-Text Benefits for SEO

The use of alt text for images is a factor in search engine ranking, as Google itself confirms. In their Search Engine Optimization Starter Guide, Google explains that optimizing image file names and alt text makes it easier for Google Images to understand the topic of the web page. Descriptive alt text can also be used as anchor text if you use the image as a link to another page.


Keyword placement is an important factor in on-page SEO ranking, and it's a good image optimization tactic to give your images alt text that both describes the image and includes a relevant keyword.


Keep in mind that the best practices for alt tags discourage filling your image's alt text with keywords. This is considered "keyword stuffing," which results in a poor user experience and carries the risk of your website being classified as spam.


Descriptive and keyword-rich alt texts can even cause your images to appear in Google Images search results. HubSpot published a case study in 2020 about their image SEO experiment, where they optimized the alt text of their images and increased their organic traffic by almost 800%.


Why Alt Text Is Important for Accessibility


Alt text is important because it replaces images when they cannot be rendered correctly on a web page.


If a website can't display its images, the alt text on the page shows the user what the image should represent instead. Without this text, the user does not know what the defective element should represent.


In 1999, the World Wide Web Consortium (W3C) published a guide on how to make Internet content more accessible to disabled or visually and hearing-impaired users. One of the guides states that content should have both an audio and a visual alternative. In other words, there should be a suitable text variant for each image and vice versa.


Blind or visually impaired users cannot read images on websites without alt text, just as they cannot read a book without Braille. Without alt text in your images, your website is difficult for screen readers and browsers to interpret.


Difference Between Alt Text and an Image Description

Alt text is often used along with image descriptions, but they relate to two different things.


The alt text gives the user the most important basic information about what the image is and what it represents. Image descriptions contain more details about what happens in the image. Image descriptions are visible below the image and serve as a caption, while most users never see the alt text unless they use a screen reader or look at the page's source code.


Let's say you write a blog post about the best coffee subscriptions and somewhere on the page is a picture of a farmer holding a handful of coffee beans in his hand. The alt text coded in the picture could read: "A fair trade farmer in Costa Rica smells deeply of the freshly harvested Arabica coffee beans in his hands", while the image description could read: "A farmer in Costa Rica smells deeply of the freshly harvested Arabica coffee beans".


How to Add Alt Text to Your Images in WordPress

WordPress gives you the option to add alt text yourself when uploading an image or editing the post itself.


When editing a page or post in WordPress, click the image you want to add alt text to. The image settings block in the sidebar contains form fields for the alt text, as well as the image description and caption.


In the Alt Text field, simply write a brief description of what the image represents and what happens on the image, and insert a relevant keyword if necessary. Click Update and the alt text will be added to the image.


7 Best Practices for Image Alt Text


Alt text is a small but important part of optimizing and accessibility your site and should be used every time you publish a new blog post or page on your site.


For this reason, you shouldn't just write anything in your alt text. Alt text best practices mean describing the image as accurately as possible and using keywords when it makes sense without overdoing it.


Here are some alt tag best practices to keep in mind:


1. Describe the image

The alt text should describe in a few words what is happening in the picture. Imagine describing the image to someone who can't see it.


2. Don't start with "Picture of"

A user, screen reader, or search engine knows if you want the text they're reading to represent the image, so it's unnecessary to prepend the text with "image of" or "picture of." It may be useful to explain the type of image they are reading, such as a chart, photo, illustration, or screenshot.


3. Add context to the image

If the image does not show a specific place or person, it should be related in some way to the theme of the rest of the page.


For example, for an article about creating a WordPress website, you could use an image of a developer in front of a computer screen. A good alt text for this image could be: alt="WordPress developer adds CSS to a website".


4. Keep short and concise - 125 characters

You only have so much space for the length of the alt text, as screen readers usually stop reading after 125 characters. Avoid long, complex sentences and use as few words as possible to convey the meaning of the image.


5. Insert keywords into your alt text

Use keywords in your alt text if they make sense in relation to the image. It's more important that your alt text describes what your image is, but include a keyword in the text if it's appropriate.


6. But don't stuff your alt text with keywords

Use your keywords only where they are needed or where it makes sense. Excessive optimization of alt text with keywords does not provide any benefit to the user and is a red rag for Google and other search engines that associate such behavior with spam.


7. Keep your alt text error-free

Typing and grammar errors can thwart the purpose of making your images visible to users with visual impairments and confuse search engine crawlers.


Great SEO successes come from small efforts

As with all things in search engine optimization, the most important thing when writing alt text is optimization for the user.


The advantage of alt text is not to stuff keywords into your website or even to appease the gods of Google's algorithm, but that the user benefits from not being able to see the image or the image cannot be displayed.


If you want to make your website accessible to more people, sign up for Prerender today and place your website where your users see it!