Google Shows How to Use Alt Text for SEO: Insights, Best Practices, and Why AI Falls Short

In the ever-evolving world of search engine optimization (SEO), image alt text remains a vital, often overlooked, tool. Google’s John Mueller, a key figure in the SEO community, recently addressed questions about alt text on Reddit, shedding light on its importance in SEO and the potential pitfalls of relying on artificial intelligence (AI) to generate it at scale. Mueller’s insights underscore a critical point: alt text is not just about describing images, but about providing valuable context for both search engines and users.

This article delves deeply into why alt text matters, how to use it effectively for SEO, and why AI may not be the best solution for creating alt text. We’ll explore key best practices and offer additional examples to help you make the most of alt text for both SEO and accessibility.

What is Alt Text?

Alt Text Explained

Alt text, short for “alternative text,” is an HTML attribute used to describe images on a webpage. It serves two primary functions: to improve accessibility for visually impaired users and to help search engines understand the content of an image. For users with visual impairments who rely on screen readers, alt text provides a spoken description of images. For search engines, which cannot “see” images the way humans do, alt text serves as a key indicator of what the image represents and how it fits into the content of the page.

A typical HTML image tag with alt text looks like this:

In this example, the alt text describes not just the image (“mountain view”) but the specific elements that make the image relevant and informative for both users and search engines.

The Role of Alt Text in SEO

From an SEO standpoint, alt text provides search engines with valuable context about an image. While Google has advanced capabilities in image recognition, it still relies on alt text to fully understand the relevance of images to the webpage’s content. Well-optimized alt text can:

• Improve Image Search Visibility: Alt text helps images rank in Google Image Search, which can drive additional traffic to your website.
• Enhance Page SEO: Search engines use alt text to better understand the context of the page, contributing to its relevance and overall ranking potential in search results.
• Increase Accessibility: Websites that are accessible to all users, including those with disabilities, are not only more user-friendly but also tend to rank better due to Google’s emphasis on user experience.

Mueller emphasizes that alt text is a critical bridge between the image and the surrounding content, providing both users and search engines with essential context that would otherwise be missed.

Why Alt Text Is Still Essential in the AI Era

Mueller’s Response to the Reddit Question

The question that prompted Mueller’s Reddit response was whether alt text remains relevant in an era of computer vision and advanced AI models. The user wondered if Google and other search engines have reached a point where they can understand images without relying on human-provided alt text. While this is a reasonable assumption, Mueller’s response was clear: alt text is still incredibly important.

Here’s what Mueller said:

“For image search, there’s the context that comes from the page + image combination that matters. A photo of a beach might be a relaxing poster, it might be the beach from a hotel, it could be the site of a chemical spill. Just knowing that the image is of a beach doesn’t really give sufficient background information to be able to show it in image search appropriately.”

Mueller’s explanation highlights a crucial point: AI may be able to “see” an image of a beach, but it cannot determine whether the beach is part of a travel blog, a hotel promotion, or a news article about environmental damage. Alt text, combined with the context provided by the surrounding content, is essential for search engines to understand the image’s meaning and purpose within the page.

Google’s Current AI Capabilities

Google has made significant advancements in AI-driven image recognition, most notably through tools like Google Lens and Google Translate. These tools can identify objects, animals, and landmarks within images and even translate text embedded in photos. However, as Mueller points out, these capabilities are currently more applicable to Google’s specialized tools, not general search.

In Google Search, alt text remains one of the few ways for search engines to fully understand an image’s context. Search engines may recognize that an image contains a “beach,” but the alt text allows Google to understand whether this beach is a travel destination, part of an advertisement, or even a historical landmark.

Why AI Falls Short for Alt Text

One of Mueller’s most significant points was about the limitations of using AI to generate alt text at scale. While AI can quickly generate descriptions based on the image file, these descriptions are often generic and lack the context necessary to be useful in a search or accessibility context.

For instance, an AI system might generate the following alt text for an image of a beach:

AI-Generated Alt Text: “Image of a beach.”

While this alt text is accurate, it lacks the nuance and context necessary to be meaningful. Compare that with a manually written alt text:

Human-Written Alt Text: “A pristine white-sand beach in Bali at sunset, with clear turquoise waters and palm trees swaying in the breeze.”

The second description provides a clear sense of place, time, and atmosphere. It adds context that enhances both the user experience and the image’s relevance to the content of the page.

The Importance of Context

One of the key takeaways from Mueller’s comments is the importance of context in alt text. Simply describing what’s in the image is not enough; the alt text must also explain why the image is relevant to the page. For example:

• E-commerce Context: An online store selling hiking boots could use the alt text: “A pair of rugged hiking boots designed for tough mountain terrain.” This text not only describes the boots but emphasizes their intended use, which is important for potential customers and search engines alike.
• Travel Blog Context: A travel blog post about visiting Paris might include an image of the Eiffel Tower with alt text like: “The Eiffel Tower lit up at night, viewed from the banks of the Seine River.” This description ties the image to the specific experience the blog is describing, enriching both the user experience and SEO.

Without this context, search engines and users are left guessing about the image’s true purpose, which diminishes its value.

Best Practices for Crafting Effective Alt Text

Given Mueller’s insights, it’s clear that writing effective alt text requires more than simply describing an image. Here are best practices for crafting alt text that enhances both SEO and accessibility:

1. Be Descriptive and Specific

Provide enough detail to describe the image meaningfully, but don’t overdo it. Aim for clear, concise alt text that conveys the image’s content and purpose.

• Weak Alt Text: “Dog”
• Better Alt Text: “Golden retriever puppy playing in a grassy park”

The second example is much more informative, offering specific details that improve user experience and SEO.

2. Context Is Key

As Mueller emphasized, alt text should reflect the image’s context within the page. Think about how the image relates to the surrounding content and describe it accordingly.

• Weak Alt Text: “A car”
• Better Alt Text: “A 2024 Tesla Model S driving along a scenic coastal highway”

The better alt text not only describes the car but also places it within the context of the page, making it more useful for both users and search engines.

3. Incorporate Keywords Naturally

While it’s important to avoid keyword stuffing, including relevant keywords in your alt text can improve your image’s SEO. Make sure the keywords fit naturally within the description.

• Weak Alt Text: “Photo of a beach”
• Better Alt Text: “Beautiful beach in Maui with crystal-clear water and palm trees”

In this example, the word “Maui” is a relevant keyword that will help the image rank for searches related to Maui, while still providing value to the user.

4. Avoid Redundancy

There’s no need to start your alt text with phrases like “Image of” or “Picture of.” Screen readers and search engines already know they are processing an image. Focus on describing the content and purpose of the image instead.

• Weak Alt Text: “Image of a woman holding a cup of coffee”
• Better Alt Text: “Woman enjoying a hot cup of coffee at a cozy café”

5. Use Alt Text for Functional and Informative Images

Not every image needs alt text. Decorative images, such as background patterns or purely aesthetic designs, should have an empty alt attribute (alt=""). This prevents screen readers from interpreting the image as meaningful content. Focus on providing alt text for images that add value to the page, whether for SEO or user experience.

6. Balance Conciseness with Clarity

Alt text should be short and to the point, typically between 100 and 125 characters. However, if the image is complex or contains vital information (such as a chart or graph), a longer description may be necessary.

• Weak Alt Text: “Graph of sales”
• Better Alt Text: “Bar graph showing a 30% increase in sales from Q1 to Q2 in 2024”

Why AI Fails to Scale Alt Text Generation

Although AI may seem like an easy solution for generating alt text at scale, the reality is that AI-generated alt text is often too vague or generic to provide real value. As Mueller pointed out, the problem with AI is that it can describe the content of an image but fails to provide the necessary context to make the description meaningful. For example:

AI-Generated Alt Text: “A dog running.”

Better Alt Text: “A black Labrador running through a field of wildflowers during a sunny day.”

The AI-generated text might be technically correct, but it fails to capture the nuances that make the image relevant to the webpage’s content.

Example: The Dangers of AI-Generated Alt Text for E-Commerce

Consider an e-commerce site selling watches. AI-generated alt text for a product image might be “Photo of a watch,” which is both vague and unhelpful. A more useful alt text would be: “Luxury stainless steel men’s watch with black leather strap, ideal for formal occasions.”

For e-commerce, where product details matter significantly, manually written alt text can highlight key features, making it far more effective for both search engines and users.

Conclusion

Alt text remains an essential component of SEO, accessibility, and user experience, even in an era dominated by AI and machine learning. As John Mueller emphasized, alt text is not just about describing an image but about providing the necessary context that AI cannot yet grasp. Manually crafted, contextually rich alt text not only enhances SEO but also improves the overall accessibility of your website.

While AI can assist in many areas of content creation, when it comes to alt text, it often falls short of delivering the nuanced, context-driven descriptions needed to optimize both user experience and search visibility. By following best practices and focusing on context, relevance, and clarity, website owners can ensure their alt text provides maximum value for both users and search engines.

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