Why Image Alt Text Matters For SEO And How To Write It?

January 15, 2024 | Basic SEO

Have you noticed that regular Google search results with images are increasing day by day?

As per the latest statistics, the increment is about 9% in the last two years.

9% increase in Google search results with images in the last 2 years

That means if you are only optimizing your content for search engines to achieve a higher ranking, you are missing a significant source of organic traffic: images in your content. 

The only way to tap this traffic source is to write SEO-friendly alt texts for images.

This article shall discuss the importance of alt texts, examples of optimal SEO-friendly img alt texts, how to craft them, and a few tips to make you an alt text expert.

But before that,

What Is Alt Text?

Alt Text (alternative text) is a piece of text that demonstrates the appearance and purpose of an image on a web page to the users and site crawlers.

Example of image alt text

It is also known as ‘alt attributes,’ ‘alt descriptions’, and ‘alt tags.’

Alt image texts are included either within the HTML code or in the field provided in the specific content management system.

Why Is Alt Text Important?

Image alt texts are important both from human and business contexts.

Human Context

Image alternate text increases the accessibility of your images to all users and ensures a better user experience, even during unfavorable conditions.

How does alt texts provide context for humans?


As per the ‘Web Content Accessibility Guidelines 1.0’ published by W3C in 1999, providing a descriptive alternate text for every visual and auditory element of your content is a must. 

It ensures that people with low or impaired vision and different learning disabilities can equally access and understand web content using screen readers.

User Experience

Alt text also helps normal users understand the purpose of an image in case the browser cannot upload the image due to some unfavorable conditions like internet usage with low bandwidth or wrong device settings.

Business Context

Image alt text helps search bots understand your images’ relevance and purpose and thus provides the following SEO benefits.

Image Traffic

Understanding your images’ purpose helps search engines rank them in relevant image-based search results.

Alternate text is a key to organic search traffic

For example, if your image ranks in Google Images, it can drive you a significant amount of organic traffic.

How To Write SEO-Friendly Alt Texts?

Now that you know the importance of SEO for your images, you must be eager to know how to craft SEO-friendly alt for images.

Here you go,

Be Short And Descriptive

As per the ‘Web Accessibility Initiative’ (WAI), the alt text should be the most concise description possible of the image’s purpose.

WAI on the length of the text alternative

However, it would help if you remembered that your alt tag should also adequately describe the image’s context. 

Hence, it is also essential to consider the audience and content surrounding the image in your alt text.

For example, ‘woman doing swimming’ can be an ideal alt text for the image for many contexts.

Woman swimmer swimming using ‘butterfly’ technique

However, if you include this image in a swimming guide, your alt tag must also describe the specific swimming technique (butterfly in this case) as well.

You need not consider the following things in your alt for images,

  1. Information already provided in the image caption like copyright information and image credit.
  2. Information already provided in the body content.
  3. Avoid including phrases like ‘image of’ or ‘photo of’ unless specifically relevant.

Include Keywords

If you want to rank your images in image-based search results, including the targeted keywords in your alt texts is necessary.

You need to choose the best free keyword research tool, like the one offered by RankWatch, to find the relevant keywords for your images.

The RankWatch keyword research tool

You only need to enter a relevant keyword related to your image and hit enter. The tool will provide thousands of organic and long-tail keywords related to your image.

However, choosing keywords with moderate keyword difficulty and search volume can make your image ranking easier. 

After including relevant keywords in your alt texts, you need to check if there is any further room for improvement.

For that, you must get a thorough on-page SEO check using a reliable tool like RankWatch.

The RankWatch on-page SEO checker

The SEO IQ feature shows the exact keyword usage in your image alt texts.

The RankWatch SEO IQ feature showing the exact keyword usage in alt texts and providing suggestions

It also suggests keywords that need to be included in the alt texts further.

Add Alt Text For The Right Images

You should not write an alt text for decorative images like the one below.

Decorative image of the RankWatch tool page

It will do more harm than good by distracting and confusing users using screen readers.

However, it would help if you remembered that Google uses computer vision algorithms to understand the purpose of the image.

Google showing image file name as alt text

Hence, if you keep the alt attribute field blank, it may consider the image file name and create a poor user experience by reading out the same while using screen readers.

Adding ‘null’ alt attribute for the alt text

Instead, it would help if you add a ‘null’ alt attribute to instruct screen readers to ignore reading the alt text. 

You must write alternative text for the following types of images used in your content,

  1. Screenshots of useful information
  2. Functional icons
  3. Charts illustrating essential data
  4. Images providing supplementary information
  5. Infographics demonstrating ‘how to’ processes

Alt Text Examples 

It would be helpful if you curate your alt texts hypothetically, considering that you describe an image to someone over the telephone.

Tips and tricks for writing alt texts by WAI

You are on the right track if you can ensure that the person on the other side of the call can clearly imagine the photo from your description.


Let us consider the following image of a blue-eyed Cockatoo bird.

Blue-eyed Cockatoo chirping

Okay Alt Text

<img src=”bird.png” alt=”Cockatoo”>

Better Alt Text

<img src=”bird.png” alt=”Cockatoo chirping”>

Best Alt Text

<img src=”bird.png” alt=”Blue-eyed cockatoo chirping”>


Let us consider the following image of a woman swimmer.

Woman swimmer swimming using ‘butterfly’ technique

Okay Alt Text

<img src=”swimmer.png” alt=”Woman swimmer”>

Better Alt Text

<img src=”swimmer.png” alt=”Woman swimmer swimming”>

Best Alt Text

<img src=”swimmer.png” alt=”Woman swimmer swimming using ‘butterfly’ technique”>

A Few Additional Tips

In this section, we will provide you with a few quick tips that will take your alt text writing skills one step further,

Quick tips for writing alt texts

  1. Try to keep the length of your alt text within 125 characters, as most screen readers can’t read alt texts beyond that length.
  2. Try to use the context of the content topic for writing alt text of images that do not feature any recognizable person, action, or place.
  3. Do not forcefully include target keywords in your alt text; instead, you can consider semantic keywords.
  4. You must ensure no spelling or grammatical errors in your alt texts.


Optimizing your content for search engines is insufficient to ensure a higher ranking in SERPs, as 28% of regular search results contain images nowadays.

Images became a constant source of organic traffic for your website.

Hence, optimizing the images used in your content has gained immense importance like never before.

Alternative text is the only means of optimizing your images for search engines.

It boosts the accessibility and user experience of your content images and thus provides you with significant image traffic.

You must perform thorough keyword research using the right tool and include your target keywords while writing short and descriptive image alt texts.

However, it is essential to use a reliable on-page SEO checker to find further optimization opportunities for your alt texts to be on the safer side.

Start optimizing your images today and enjoy the benefits of ranking in image search results.

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