What Is an Alt Attribute? Why It Matters for SEO and Accessibility
The alt attribute is HTML code that describes an image on a webpage. It serves two primary functions: enhancing accessibility for users who rely on screen readers (like visually impaired users) and helping search engines index visual content effectively. For example, if an image fails to load, the alt text displays in its place. From an SEO perspective, alt attributes provide context about on-page content, contributing to higher rankings in image and web search. In fact, optimizing image alt text can significantly boost visibility. A 2023 Moz study found that websites with optimized image alt tags saw a 12% average increase in organic traffic over six months.
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Use Cases
Search engines can't 'see' images but do read alt text. Including keywords in your image alt attribute increases your visibility on Google Image Search and supports on-page SEO relevance.
Alt attributes enable screen readers to describe images to visually impaired users. It's essential for ADA compliance and inclusive user experience.
Online stores with clear, keyword-rich alt text for product images often rank better in shopping results and increase conversions due to improved discoverability.
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Frequently Asked Questions
Is alt text required for all images?
Technically no, but it's strongly recommended for all non-decorative images to support SEO and accessibility. Decorative images can use empty alt text (alt="").
Can I use keywords in alt attributes?
Yes, but avoid keyword stuffing. Use concise, accurate descriptions that naturally include relevant keywords for best results.
How long should an alt attribute be?
Google recommends keeping alt text under 125 characters. Focus on being clear and concise.
Does alt text help with voice search?
Alt text describes the image for screen readers and SEO. Image titles appear on hover and are less relevant to search engines.
What’s the difference between alt text and image title?
Absolutely. Missing alt attributes can lead to lost search traffic, lower accessibility scores, and poor user experience on image-heavy pages.
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