What is alt image text, and why is it important? Alt (short for “alternative”) image text increases web accessibility and serves as a cornerstone of effective SEO strategy. Alt text provides search engines with critical context about image content, making it essential for any organization’s digital marketing efforts. While machine learning and AI-powered image recognition continue to advance, computer vision algorithms still rely heavily on human-written descriptions to accurately interpret visual content for both assistive technology users and search engine crawlers. If you want to increase your likelihood of appearing in image search results and improve your overall search rankings, alt image text should be an integral part of how you approach SEO.
Alt text is aptly named because if a browser cannot load a webpage’s image, the alt text will appear in its place. Alt text is sometimes also known as “alt attributes” or “alt descriptions.” For individuals using screen readers to access the web like Apple’s VoiceOver, alt text is how users will experience the image you have provided. Simultaneously, you increase your chance of ranking in image search results and capturing traffic from visual search queries.
How Search Engines Use Alt Text to Understand Images
When Google crawls a website and indexes an image, it uses HTML to determine context. In the case of an image, search engines analyze multiple factors including the title, alt text and alt tags, caption, filename, and nearby web copy to understand what an image portrays. This crawling process is one reason it’s crucial to place images near relevant copy, in addition to increasing visual clarity and better design.
You may ask, what’s the difference between a caption and alt text? Captions display onscreen and alt text is only used by those accessing your site through a screen reader. However, both will be communicated to a user by a screen reader, meaning it’s essential to provide different information in both your alt text and caption to avoid redundancy for those using accessibility devices.
Understanding Alt Text vs Image Title Attributes
Another common question involves the distinction between alt text and image title attributes. While alt text is read by screen readers and used by search engines for ranking purposes, the image title attribute typically appears as a tooltip when users hover over an image. Alt text is mandatory for accessibility compliance and SEO benefits, whereas title attributes are optional and serve a secondary purpose. Focus your efforts on creating descriptive, keyword-relevant alt text first, as this delivers the most significant SEO and accessibility impact.
How to Write SEO-Friendly Alt Text for Images
To direct people to your website and provide relevant information, your alt tags should be concise and descriptive. Avoid stuffing the alt text with keywords and instead include information-rich wording that naturally describes what the image shows. An example of good alt text for the image below if one owned a marketing firm could be, “A brightly lit office with laptop and monitor sharing key marketing metrics among natural decor.” This description works for both SEO and accessibility without being spammy.
Best Practices for Writing Effective Alt Text
When crafting alt text descriptions, keep your descriptions between 125-150 characters when possible. Be specific about what the image shows rather than using generic phrases like “image of” or “picture of.” Include relevant keywords naturally, but prioritize accuracy and clarity over keyword placement. Describe the image’s purpose and context within your content, not just its visual elements. For example, if an image shows a graph of rising website traffic, mention the data trend rather than simply stating “graph with lines and numbers.”
Decorative vs Informative Images: When to Use Alt Text
Not every image requires detailed alt text. Understanding the difference between decorative and informative images helps you optimize efficiently. Decorative images serve purely aesthetic purposes and don’t convey essential information. These might include background patterns, design flourishes, or spacer images. For decorative images, use empty alt text (alt=””) to signal to screen readers that they can skip the image without missing content.
Informative images, conversely, provide meaningful content that enhances understanding of your topic. These include screenshots, infographics, product photos, diagrams, and any visual that would leave users at a disadvantage if they couldn’t see it. All informative images require descriptive alt text that conveys their essential information to users relying on assistive technology.
Alt Text and AI-Powered Visual Search
As artificial intelligence continues to reshape how users discover content, alt text plays an increasingly important role in AI-based image recognition and visual search. Search engines use alt text to better categorize and rank images in visual search results, where users can upload photos or screenshots to find similar images or related information. By providing clear, descriptive alt text, you help AI algorithms understand your images’ context and relevance, improving your chances of appearing in these emerging search experiences.
The connection between accessibility and SEO continues to strengthen as search engines become more sophisticated. Alt text serves as a bridge between human accessibility needs and machine learning capabilities, demonstrating that optimizing for people with disabilities simultaneously improves your search engine performance.
The SEO Impact of Missing or Poor Alt Text
While search engines won’t directly penalize websites for missing alt text, the absence of image descriptions creates missed opportunities that compound over time. Pages without alt text lose potential traffic from image search results, sacrifice accessibility for users with visual impairments, and provide incomplete information to search engine crawlers attempting to understand your content’s relevance and quality.
Poor quality alt text can be equally problematic. Keyword-stuffed descriptions, vague phrases like “image” or “photo,” or irrelevant descriptions confuse both users and search engines. These practices can diminish user experience and may signal low-quality content to search algorithms. Investing time in thoughtful alt text creation delivers compounding SEO benefits as search engines increasingly prioritize accessible, well-structured content.
Alt Text Generators and Automation Tools
Various alt text generator tools and AI-powered solutions have emerged to help automate image description creation. While these tools continue improving in capability, they should be viewed as starting points rather than complete solutions. Computer vision technology can identify basic objects and scenes but often misses nuanced context, brand-specific details, or the image’s specific purpose within your content strategy.
If you use alt text generators, always review and refine their output. Add relevant keywords they might miss, ensure descriptions align with your content’s focus, and verify accuracy. Human oversight remains essential for creating alt text that serves both accessibility and SEO objectives effectively.
How to Add Alt Text in WordPress
To add image alt text on WordPress, navigate to the “Media” tab from the Dashboard, click on the desired image, add your text in the “Alternative Text” field, and click “Update.”
Alternatively, in WordPress, navigate to the page you want to edit, click on the image block, click the pencil icon to edit, enter the text into the “Alternative Text” field and click “Update.”
How to Add Alt Text in Shopify
To add alt text to product images in Shopify, once you’re in admin, go to “Products,” click the desired media, click “Add ALT text,” and click “Save ALT text” after entering the text.
E-Commerce Product Image SEO Tips
For online stores using platforms like Shopify, alt text becomes even more critical for driving product discovery and sales. Product images without descriptive alt text miss opportunities to appear in Google Shopping results, visual search queries, and image-based product comparisons. When writing alt text for product images, include the product name, key features, color, and any distinctive characteristics that shoppers might search for. For example, “Blue organic cotton women’s yoga pants with side pockets” provides more SEO value than simply “yoga pants.”
Learn More About Accessibility and SEO Techniques
Explore these additional NisonCo resources to enhance your accessibility and SEO knowledge:
5 Voice-to-Text SEO Techniques to Increase Site Accessibility – Discover how voice search optimization improves both accessibility and search rankings.
7 High-Quality Tips to Boost E-Commerce Sales with SEO – Learn advanced strategies for optimizing online stores for maximum visibility and conversions.
5 Expert SEO Techniques to Fix Common Optimization Errors – Address technical SEO issues that may be holding back your search performance.
Health & Wellness SEO Services – Specialized SEO strategies for health and wellness businesses.
Plant-based & Vegan SEO – Targeted SEO solutions for plant-based and vegan brands.
Are you seeking help from our experienced PR, SEO and marketing team? Let us know if you need help researching trends and topics, crafting communications, or optimizing blogs & webpages by contacting NisonCo here.
