How Image Alt Tags Improve SEO And Accessibility

Image Alt Tags

Image alt tags (alt attributes) are short text descriptions added to an image's HTML that convey the image's content and function for screen readers, provide context when images fail to load, and improve SEO by offering searchable text for search engines.

Why Are Alt Tags Important for SEO?

Image alt tags (alt attributes) are short text descriptions added to an image’s HTML that convey the image’s content and function for screen readers, provide context when images fail to load, and improve SEO by offering searchable text for search engines.

They provide crawlable text for images, helping your pages be indexed and ranked more accurately. Specific reasons include:

• Enable image indexing and drive traffic from image search (better chances for placement in Google Images and Discover).


• Provide contextual relevance signals that reinforce the page’s topical keywords and improve on-page SEO.


• Improve semantic understanding for algorithms that can’t see images, increasing relevance for visual queries and eligibility for rich results.


• Boost click-through rates from image results and improve user engagement metrics (time on page, lower bounce rates) that can indirectly support rankings.


• Serve as reliable fallback content when images fail to load, preserving keyword relevance and user experience.


• Complement structured data and captions to create stronger signals for search engines.


• Reduce the risk of accessibility-related penalties or usability issues that can harm conversions and engagement, which in turn affects SEO performance.

Alt Text Best Practices: Be Descriptive, Concise, and Accessible

1. Be descriptive and specific — use clear, concrete terms that convey the subject, action, and key details so users and search engines understand the image.


2. Include relevant keywords, but don't overdo it — incorporate one or two natural keywords that reflect the image's context without stuffing or forcing phrases.


3. Avoid redundancy — don't repeat information already present in nearby text; make alt text complementary and unique.


4. Keep it concise — aim for a short sentence or phrase (about 125 characters or fewer) that communicates the essential information.


5. Focus on contextually relevant images — choose images that directly illustrate the surrounding content and add value to the user's experience.


6. Always use alt text for decorative images — for purely decorative images, use an empty alt attribute (alt="") to let assistive technologies skip them.