AltTagger Guide

The Comprehensive Guide to Alt Tags: Why Every Website Needs Them

In the world of web design and development, certain elements might seem small but have an outsized impact on user experience, accessibility, and even business performance. This guide explores why alt tags are not just a technical requirement but a strategic advantage for any website.

Alternative text (alt text) for images is precisely one of those elements that seem minor but play a crucial role in making websites more inclusive, more discoverable, and more effective. Despite being just a few words of hidden text, alt tags help create a more accessible digital landscape for everyone while providing significant SEO and business benefits.

What Are Alt Tags?

Alt tags (also known as alt text or alt attributes) are HTML attributes added to image tags to provide a text alternative for images on a webpage. They appear in the HTML code like this:

<img src="golden-retriever.jpg" alt="Golden retriever puppy playing with a red ball">

This text serves as a replacement for the image when it cannot be viewed or accessed visually. While usually invisible to sighted users unless an image fails to load, alt text is essential for many website visitors and for search engines indexing your content.

The Multifaceted Benefits of Alt Tags

1. Enhanced Web Accessibility

  • Making content accessible to everyone. Alt tags are fundamental to making your website accessible to people with visual impairments or disabilities. Screen readers, which are assistive technologies used by blind or visually impaired people, read alt text aloud, allowing these users to understand what's in the image.
  • Legal compliance. In many jurisdictions, web accessibility is not just a best practice but a legal requirement. Legislations like the Americans with Disabilities Act (ADA) in the U.S., the Equality Act in the UK, and the European Accessibility Act in the EU mandate that websites must be accessible to people with disabilities.
  • Universal Design principles. Embracing alt tags aligns with the principles of Universal Design, which aims to create environments and products usable by all people without the need for adaptation.

According to the World Health Organization, approximately 285 million people worldwide are visually impaired. Without proper alt text, a significant segment of potential users might miss crucial information on your website.

2. Improved SEO Performance

  • Helping search engines understand images. Search engines can't "see" images the way humans do. They rely on alt text to understand what's in an image and how it relates to the surrounding content.
  • Keyword opportunities. Alt tags provide additional opportunities to incorporate relevant keywords naturally. When your keywords appear in alt text that accurately describes your images, it reinforces the topic relevance of your page.
  • Image search traffic. Google Images and other image search services use alt text to index images. Well-crafted alt descriptions can help your images appear in relevant image searches.
  • Core Web Vitals optimization. When images fail to load, browsers display alt text instead. This improves perceived performance, which is a factor in Google's Core Web Vitals metrics.

3. Enhanced User Experience

  • Fallback for technical issues. Images might fail to load due to slow connections, server errors, or users who have chosen to disable images to save data. Alt text ensures users still understand what should be there.
  • Clarification of visual content. Good alt text provides context and explanation that might not be immediately obvious from the image alone, particularly for complex visualizations.
  • Mobile optimization. On mobile devices with limited data plans, users might browse with images turned off. Alt text ensures these users don't miss important visual information.

4. Business Benefits

  • Broader audience reach. By making your website accessible to people with visual impairments, you expand your potential customer base. The purchasing power of people with disabilities is significant – in the U.S. alone, it's estimated to be over $490 billion.
  • Brand reputation. Demonstrating a commitment to accessibility enhances your brand's reputation as socially responsible and inclusive.
  • Risk mitigation. With an increasing number of web accessibility lawsuits being filed each year, proper alt tags can help protect your business from legal risks.

"Alt text serves as the voice of your images for those who cannot see them. It's not just about accessibility compliance—it's about creating an inclusive web experience for everyone."

Web Accessibility Initiative

Best Practices for Writing Effective Alt Tags

Be Specific and Descriptive

Good alt text should accurately describe what appears in the image with enough detail to replace the visual information. Generic descriptions don't provide value to users who cannot see the image.

Examples:

  • Bad Example: alt="dog"
  • Good Example: alt="Dalmatian puppy playing fetch with a blue frisbee in a park"

Consider Context

The ideal alt text varies depending on the image's purpose and surrounding content. An image's meaning might change based on where and how it's used on your website.

For example, the same product image might need different alt text on:

  • A category page: alt="Black leather office chair with adjustable armrests"
  • A product detail page: alt="ErgoComfort Pro office chair with lumbar support and breathable mesh backrest"

Keep It Concise

While descriptive, alt text should remain concise. Most screen readers work best with alt text under 125 characters. Prioritize the most important information about the image.

Include Text That Appears in Images

If your image contains text that conveys important information, include that text in your alt attribute so screen reader users don't miss out on this content.

Use Empty Alt Text When Appropriate

Not all images require alt text. Decorative images that don't add informational content should use empty alt attributes (alt="") so screen readers skip them. This applies to background textures, decorative lines, or purely aesthetic elements.

Zebras walking near Mount Kilimanjaro with hot air balloon.

alt="Walking Zebras."

Zebras walking near Mount Kilimanjaro with hot air balloon.

alt="Zebras walking near Mount Kilimanjaro with hot air balloon."

Compare the difference between poor alt text and descriptive alt text.

Alt Tags for Different Types of Images

Product Images

Focus on key features, colors, and uses that would help someone make a purchasing decision:

<img src="coffee-maker.jpg" alt="Stainless steel programmable coffee maker with 12-cup carafe and built-in grinder">

Charts and Graphs

Summarize the data trend or main conclusion, not every data point:

<img src="sales-graph.png" alt="Graph showing steady increase in sales from January to June 2023 with 45% overall growth">

Logos

Include the company or brand name:

<img src="nike-logo.png" alt="Nike logo">

Decorative Images

Use empty alt text for purely decorative images:

<img src="decorative-divider.png" alt="">

Implementing Alt Tags Across Your Website

Conducting an Alt Text Audit

Start by evaluating your current website. Use tools like WAVE (Web Accessibility Evaluation Tool) or Lighthouse to identify images missing alt text. Prioritize high-traffic pages and those with the most images.

Creating an Alt Text Policy

Develop guidelines for your content team that specify how alt text should be written for different types of images on your site. Include examples specific to your industry and content.

Using CMS Features

Most modern Content Management Systems (CMS) like WordPress, Shopify, or Drupal have built-in fields for adding alt text to images. Make sure your content creators know how to use these features correctly.

Automating Where Appropriate

For websites with thousands of images, consider using AI-powered tools that can generate initial alt text suggestions. These should always be reviewed by humans for accuracy and context, but they can speed up the process significantly.

Measuring the Impact of Alt Tags

Accessibility Testing

Use screen readers like NVDA, JAWS, or VoiceOver to experience your website the way visually impaired users do. This can reveal issues with your alt text that might not be obvious otherwise.

SEO Improvements

Track image search traffic before and after implementing better alt tags. Look for increases in relevant keyword rankings and overall organic traffic.

User Engagement Metrics

Monitor metrics like bounce rate, time on page, and conversion rates to see if improved alt text correlates with better user engagement, particularly on pages with many images.

Common Alt Text Mistakes to Avoid

Keyword Stuffing

While alt text is important for SEO, stuffing it with keywords creates a poor experience for screen reader users and may trigger search engine penalties.

Examples:

  • Keyword Stuffing: alt="puppy dog baby dog pup pups puppies doggies litter retriever labrador puppy food cheap dogfood"
  • Natural Usage: alt="Golden retriever puppy sleeping in its bed"

Starting with "Image of" or "Picture of"

Screen readers already announce that an element is an image, so including phrases like "image of" or "picture of" is redundant.

Examples:

  • Redundant: alt="Image of a sunset over the ocean"
  • Better: alt="Sunset over the Pacific Ocean with orange and purple sky"

Using Generic Descriptions

Generic descriptions don't help users understand what's in the image.

Examples:

  • Too Generic: alt="Banner"
  • More Descriptive: alt="50% off summer collection banner with tropical background"

Neglecting Complex Images

Complex visuals like infographics, charts, or diagrams require more detailed alt text, and sometimes additional explanations in the surrounding content.

The Future of Alt Text

AI and Automated Alt Text

Artificial intelligence is increasingly being used to generate alt text automatically. While this technology continues to improve, human review remains important for ensuring accuracy and context-appropriate descriptions.

Structured Data and Rich Results

Combining proper alt text with structured data markup can enhance how your images appear in search results, potentially with badges, captions, or other rich features that increase visibility.

Emerging Accessibility Standards

As web accessibility standards evolve, best practices for alt text may change. Staying informed about updates to WCAG (Web Content Accessibility Guidelines) will help ensure your website remains compliant.

Conclusion

Alt tags represent the perfect intersection of accessibility, user experience, and search engine optimization. They exemplify how making your website more inclusive for people with disabilities often improves the experience for all users while simultaneously boosting your business results.

Implementing proper alt text is not just about checking a box for accessibility compliance—it's about embracing the fundamental principle that web content should be available to everyone, regardless of how they access it. In today's digital landscape, where user experience and inclusivity are increasingly prioritized by both consumers and search engines, comprehensive alt text implementation is a relatively small effort that yields significant returns.

By following the best practices outlined in this guide, you can ensure that every image on your website contributes to a more accessible, discoverable, and effective web presence.