What is Alternative Text (Alt Text)? Best Practices & Guide

Definition

Alternative text, also known as alt text or alt attribute, is a textual description used in HTML to describe the content of an image. This description appears if the image fails to load or for users who rely on screen readers due to visual impairments. Alt text ensures that all users, regardless of their abilities or technical limitations, can understand the context of an image. It’s an essential part of web accessibility and SEO optimization.

Alt text is defined using the alt attribute within the HTML <img> tag. It can help search engines understand what an image represents, which is why it’s critical for ranking higher in search results (WebAIM).

Alt Text Example

Let’s look at a basic example of how alt text is implemented in HTML:

<img src="example.jpg" alt="A beautiful sunset over the ocean with orange hues in the sky">

In this example, the alt text is “A beautiful sunset over the ocean with orange hues in the sky.” This text describes the content of the image for users who can’t see it, ensuring they can still access the information the image conveys (W3C Web Accessibility Initiative).

Why is Alt Text Important?

Alt text serves several crucial purposes, both from a user experience and an SEO perspective:

1. Accessibility

Alt text is vital for web accessibility. It allows users with visual impairments to understand what’s on your website. When a screen reader encounters an image, it reads out the alt text, so users can gain the image’s context. Without alt text, many users would miss out on key visual information. For more details on accessibility, you can check W3C’s Accessibility Standards.

2. Search Engine Optimization (SEO)

Search engines like Google can’t see images the way humans do, so they rely on alt text to understand the content. Alt text helps search engines rank images in image searches, improving visibility. By properly optimizing your images with relevant keywords in the alt text, you can boost your site’s SEO. Learn more about the impact of alt text on SEO through Google’s Webmasters guidelines.

3. User Experience

When an image doesn’t load due to slow internet connections or technical issues, the alt text will be displayed in place of the image. This ensures users still get the context of what should have been shown.

Alt Text Best Practices

To optimize alt text for both SEO and accessibility, follow these best practices:

1. Be Descriptive, but Concise

Describe the image as accurately as possible, but keep the description brief. Aim for clarity and relevance rather than trying to write long sentences. For example, “Black cat on a red couch” is more effective than “A beautiful black cat sitting on a red couch in a cozy living room.”

2. Use Keywords Naturally

While alt text is an opportunity to add keywords for SEO, it’s important to avoid keyword stuffing. The goal is to describe the image for the user, not to overstuff with keywords. For example, “Outdoor adventure with hiking” is better than “Outdoor adventure hiking hiking adventure.”

3. Avoid Redundancy

Don’t repeat information that’s already mentioned in the surrounding text. Alt text should add value and not be redundant. For example, if the heading is “Summer Vacation Photos,” avoid writing “Image of summer vacation photos” in the alt text.

4. Context Matters

Always consider the context of the image. If the image is part of a blog post about healthy eating, make sure the alt text reflects the content of the image in that context. For example, “A healthy salad with fresh vegetables” fits the context better than just “A salad.”

How to Write Alt Text for Different Image Types

The type of image you’re using on your website often determines how you write the alt text. Here are some tips for different types of images:

1. Product Images

For eCommerce websites, alt text for product images should include the product’s name, its key features, and other relevant attributes like color or size. For example:
“Red leather wallet with gold zipper, medium size.”

2. Infographics

Infographics require a more detailed description, as they often contain a lot of valuable information. Describe the purpose of the infographic and any key data it presents. For example:
“Infographic showing the annual sales growth for 2020 with a bar chart and key figures.”

3. Decorative Images

If the image serves only a decorative purpose (i.e., it doesn’t convey important content), it’s best to use an empty alt text attribute (alt=””). This tells screen readers to skip the image, improving accessibility without unnecessary distraction.

4. Graphs and Charts

For charts and graphs, include a brief description of the data they represent. If the graph is complex, you might consider providing additional context in the surrounding content. 

For example:
“Bar graph showing the increase in sales over the last 12 months, with 2020 showing the highest growth.”

Common Alt Text Mistakes to Avoid

1. Using Generic Alt Text

Generic descriptions like “image” or “picture” don’t provide any valuable information. Always aim for a description that conveys the image’s meaning.

2. Keyword Stuffing

While it’s tempting to add as many keywords as possible to alt text, this can hurt your SEO efforts. Always focus on writing natural, meaningful descriptions instead of stuffing keywords.

3. Overly Complex Descriptions

Alt text should be easy to understand. Long, complex sentences or overly detailed descriptions are not ideal. Keep it simple and to the point.

4. Missing Alt Text

Leaving alt text out completely is a major mistake. This negatively impacts accessibility and SEO. Always ensure each image has meaningful alt text. For more details, check W3C’s Guide on Image Accessibility.

How to Add Alt Text to Images in a CMS

The process of adding alt text varies depending on the content management system (CMS) you’re using. Below are the steps for adding alt text in some popular CMS platforms:

1. WordPress

In WordPress, adding alt text is easy:

1. Upload your image to the media library.
   
2. Select the image and fill out the “Alt Text” field with a descriptive label. You can learn more about image SEO in WordPress from Yoast.
   

2. Shopify

In Shopify, you can add alt text to your product images:

1. Go to your Shopify admin panel.
   
2. Click “Products,” and select the product.
   
3. Under the “Images” section, click “Edit” and add the alt text.
   

3. Wix

For Wix:

1. Upload your image and select it.
   
2. Click on “Settings” and then “Image Settings.”
   
3. Enter your alt text in the “Alt Text” field.
   

4. Squarespace

In Squarespace:

1. Add your image block.
   
2. In the settings, you’ll find an “Alt Text” field where you can enter your description. For more on using alt text on Squarespace, refer to Squarespace’s Help Center.
   

Conclusion

Alt text is an essential element of web accessibility, SEO, and user experience. By following best practices for writing descriptive, relevant, and concise alt text, you can improve both the accessibility of your site and its performance in search engines. Remember, always provide alt text for every image and keep it clear and descriptive to avoid any SEO pitfalls. Proper alt text not only helps visually impaired users but also ensures that your website ranks higher in search results. For more on web accessibility, refer to WebAIM.