Alt text, also known as “alternative text,” is a brief description that is added to an image’s HTML code to help search engines and assistive technologies understand what the image is about. Alt text serves as a textual alternative to images when they cannot be displayed or when a user cannot see them due to a visual impairment or slow internet connection.

In terms of SEO, alt text plays a critical role in image optimization, which is an essential aspect of on-page optimization. By providing relevant and descriptive alt text, website owners can help their images appear in Google Image search results, increasing their visibility and driving more traffic to their website. Additionally, alt text can improve website accessibility, which is crucial for providing a positive user experience for all visitors. In this article, we’ll dive deeper into the importance of alt text in SEO and how to write effective alt text for your images.

What is Alt Text?

Alt text, also known as alternative text or alt attributes, is a brief description added to the HTML code of an image that explains what the image is about. This text is typically read by screen readers for people with visual impairments or by search engine bots when the image cannot be displayed due to slow internet connection, broken link, or other issues. Alt text can also be used by browsers to display a text description of the image when users hover over it.


Types of Alt Text

There are different types of alt text, including:

  1. Decorative: These are images that are added to a web page for aesthetic purposes only, and they do not convey any information. In this case, the alt text should be left empty, or a null alt text can be used.

  2. Functional: These are images that have a specific function, such as buttons, icons, or logos. In this case, the alt text should describe the function of the image rather than its appearance.

  3. Informative: These are images that convey important information that cannot be conveyed through text, such as graphs, charts, or infographics. In this case, the alt text should provide a concise and descriptive summary of the information presented in the image.


Examples of alt text:

  • Decorative: <img src=”decorative-image.jpg” alt=””>
  • Functional: <img src=”search-icon.jpg” alt=”Search icon”>
  • Informative: <img src=”pie-chart.jpg” alt=”Pie chart showing the percentage of sales by product category: 50% Electronics, 30% Clothing, 20% Home goods”>

Importance of Alt Text in SEO

Alt text plays a crucial role in SEO, particularly in image optimization. Search engines like Google use alt text to understand the content of images and use this information to rank web pages in search results. By including relevant and descriptive alt text, website owners can increase the visibility of their images in search results, potentially driving more traffic to their website.


The Role of Alt Text in Image Optimization

Image optimization is a critical aspect of on-page SEO, and alt text is a key component of image optimization. In addition to helping search engines understand the content of images, alt text can also help website owners to:

  • Improve the user experience: Providing descriptive alt text makes it easier for users to understand the content of an image, even if they cannot see it.

  • Increase website accessibility: Alt text helps people with visual impairments to access the content of an image using screen readers or other assistive technologies.

  • Reduce page load times: When an image cannot be loaded due to slow internet connection, the alt text can provide context to the user while the image loads.

The Impact of Alt Text on Website Accessibility

Alt text is critical for website accessibility, as it helps people with visual impairments to understand the content of an image. Screen readers read out the alt text when the image cannot be displayed, allowing visually impaired users to access the content of the image. Without alt text, visually impaired users may miss out on important information presented in images, leading to a poor user experience.

In addition to alt text, website owners should also consider other accessibility best practices, such as using descriptive link text and providing alternative text for videos and audio files. By making their website accessible to all users, website owners can improve the user experience and reach a wider audience.

Best Practices for Writing Alt Text

Writing descriptive and effective alt text is critical for improving website accessibility and optimizing images for search engines. Here are some tips for writing alt text:

  1. Be descriptive: Alt text should accurately describe the content of the image in a concise and informative way. Avoid using generic or vague descriptions that do not provide enough context.

  2. Keep it short: Alt text should be brief and to the point, usually between 100-125 characters. Longer alt text may be ignored by screen readers or may not be fully displayed in search results.

  3. Avoid keyword stuffing: While it’s important to include relevant keywords in alt text, avoid overloading the text with keywords. This can be seen as spammy and may hurt your SEO.

  4. Use natural language: Alt text should be written in natural language, avoiding jargon, acronyms, or technical terms that may not be understood by all users.

  5. Include important details: Alt text should include any important details that are not obvious from the image, such as the color, size, or location of the subject.


Examples of good alt text:

  • Alt text for a picture of a cat: “Orange tabby cat lounging on a windowsill”

  • Alt text for an infographic about renewable energy: “Infographic showing the percentage of renewable energy sources in the United States: 40% solar, 25% wind, 20% hydropower, 15% geothermal”

Examples of bad alt text:

  • Alt text for a picture of a cat: “Picture of a cat”

  • Alt text for a graph: “Graph”

How to Add Alt Text to Images

Adding alt text to images is a straightforward process that can improve your website’s accessibility and SEO. Here’s a step-by-step guide for adding alt text to images:

  1. Identify the image you want to add alt text to and open the HTML code editor for that page.

  2. Locate the image tag in the HTML code, which looks like this: <img src=”image.jpg”>.

  3. Add the alt attribute to the image tag by typing alt=”your alt text” inside the tag. For example: <img src=”image.jpg” alt=”A happy family playing in the park”>.

  4. Save the changes to the HTML code and publish the page.

Note: If you’re using a content management system (CMS) like WordPress or Drupal, you can add alt text to images through the image editor. When you upload an image, you’ll be prompted to enter alt text in a designated field.


Tools and Plugins to Make Adding Alt Text Easier

If you have a large number of images on your website, manually adding alt text to each one can be time-consuming. Fortunately, there are several tools and plugins available to make the process easier:


  1. Yoast SEO: A popular WordPress plugin that includes a feature for adding alt text to images.

  2. ImageAltText: A free tool that automatically generates alt text for images using machine learning.

  3. Accessibility Checker: A tool that checks your website for accessibility issues, including missing alt text.

  4. Content Management Systems: Many CMS platforms, such as WordPress, Drupal, and Squarespace, include built-in alt text fields that make it easy to add alt text to images.


By using these tools and plugins, you can save time and ensure that all of your images have descriptive and accurate alt text.

Alt text plays a crucial role in website accessibility and SEO. By providing descriptive and accurate alt text for images, you can ensure that all users, including those with visual impairments, can understand the content on your website. Additionally, alt text helps search engines better understand the content of your website, improving its relevance and visibility in search results.


To ensure that your alt text is effective, remember to keep it descriptive, concise, and natural-sounding. Avoid keyword stuffing and be sure to include any important details that are not obvious from the image. By following these best practices and using tools and plugins to make the process easier, you can optimize your images for accessibility and SEO.


In conclusion, alt text is an important part of any website’s SEO strategy and can have a significant impact on its overall accessibility and visibility. By prioritizing alt text and following best practices, you can create a more inclusive and effective website for all users.

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