Writing alt text for SEO involves creating descriptive, concise text that explains the function and appearance of an image to search engines and users. Google uses alt text along with computer vision algorithms to understand the subject matter of images, which helps index your content properly. By providing this textual context, you bridge the gap between visual assets and search crawlers. This practice is essential for both search engine visibility and ensuring that individuals using screen readers can fully engage with your digital content.
Why is alt text required for accessibility?
Accessibility remains a fundamental requirement for modern websites. Many users rely on screen readers to navigate the web, as these tools convert written text into spoken words. If an image lacks descriptive alt text, the screen reader may skip the image or simply announce it as an image file name, which provides no value to the user. Providing a meaningful description allows someone with a visual impairment to understand the context of the image. This creates a better experience for your audience and confirms that your site is inclusive of all users.
Beyond accessibility, search engines value content that provides a clear context. While computer vision technology is advanced, it is not perfect. Explicitly defining what is in an image helps search engines categorize your visual assets correctly. When you describe the content accurately, you reduce the risk of ambiguity. If you run a web design agency or manage a site, you should treat alt text as a standard part of your publishing process rather than an afterthought.
How to write alt text for SEO effectively?
Writing effective alt text requires balance. You want to be descriptive enough to inform the user, but you must avoid stuffing the text with keywords. Keyword stuffing often results in a poor user experience and may be viewed negatively by search algorithms. Instead, focus on describing the image as if you were explaining it to someone who cannot see it. A good description usually covers the main subject, the action taking place, or the context of the visual element.
Consider the intent of your page. If you have an image of a product on an e-commerce site, the alt text should include the product name and perhaps a key feature. If you have a decorative image, such as a background pattern or a divider, you might choose to leave the alt attribute empty. This prevents screen readers from announcing unnecessary information to the user. Always prioritize clarity and brevity in your descriptions.
Best practices for writing image descriptions
- Be specific: Describe the subject matter, the setting, and any relevant details clearly.
- Keep it brief: Aim for 125 characters or fewer to ensure screen readers handle it well.
- Avoid redundant phrases: Do not start with phrases like ‘image of’ or ‘picture of’ as the screen reader already identifies the element as an image.
- Use keywords naturally: Incorporate relevant keywords only if they truly describe the visual content.
- Skip decorative images: Use an empty alt attribute (alt=””) for images that do not convey information.
What are common mistakes to avoid?
One common mistake is leaving the alt text field blank for informative images. When a search crawler finds an image without alt text, it has to rely solely on other factors like file names or surrounding text to figure out what the image represents. Another issue is using generic file names like ‘IMG_001.jpg’. You should rename your files to be descriptive before uploading them to your CMS. This gives you a secondary layer of optimization that supports your alt text strategy.
Another error is over-optimization. If your alt text reads like a list of keywords, it provides no meaningful information to a human reader. For instance, instead of ‘shoes running men cheap blue sneakers’, use ‘Blue men’s running sneakers on a paved track’. This describes the image accurately while naturally including keywords. Remember that your primary goal is to provide value to the visitor, as this is the metric that search engines ultimately aim to reward.
How Alien Road applies image optimization
At Alien Road, our approach to image optimization begins with a technical audit of the site’s media library. We examine existing alt text entries to identify missing or low-quality descriptions. In a typical engagement, we work with clients to establish a naming convention for all future uploads. This ensures that every image, whether it is a product photo or a blog illustration, follows a consistent standard that supports both SEO and accessibility goals.
We also utilize automated checks to verify that no images are missing the alt attribute during our development phase. For example, if a client is launching a new landing page, we verify the alt text as part of our quality assurance checklist. By integrating these tasks into the design and build process, we ensure that the client’s site is search-ready from the moment it goes live. This methodical approach helps our clients maintain high standards without manual oversight for every single file.
Where should you add alt text in your CMS?
- WordPress: Go to the Media Library, select an image, and enter your text in the ‘Alternative Text’ field in the attachment details pane.
- Shopify: Navigate to your product page, click on the image, and use the ‘Add alt text’ link to input your description.
- Wix: Right-click an image in the editor, select ‘Settings’, and fill in the ‘What’s in the image?’ box.
- HTML code: Use the alt attribute within your image tag:
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How to monitor your image SEO performance?
Monitoring how well your images perform in search involves tracking traffic from image search results. You can use tools like Google Search Console to see which queries lead users to your site via images. If you notice a high volume of traffic from specific image searches, review the alt text and surrounding content on those pages. This can provide clues about what your audience is looking for when they interact with your visual content.
Regular audits are also beneficial. You do not need to check every image daily, but performing a review every quarter is a standard practice for many content-heavy sites. Look for images that lack alt tags or those that have duplicate text across multiple pages. Fixing these issues incrementally allows you to improve your site’s overall quality score. Consistent maintenance is the key to sustaining long-term organic growth for your visual assets.
Where to start this week
Start by identifying the top 20 pages on your website that generate the most traffic. Audit the images on these specific pages to ensure they have descriptive, relevant alt text. Once you complete this, you can move on to your product pages or your most recent blog posts. By starting with your highest-impact content, you ensure that you are making the most effective use of your time. If you have a large site, consider using an automated crawler tool to scan for missing alt text across all pages.
Finally, make it a habit to add alt text the moment you upload a new image to your dashboard. Whether you use a custom build or a platform like Shopify, the process takes only a few seconds per image. By making this a requirement for your content team, you prevent the accumulation of technical debt. This small, consistent action is one of the most reliable ways to improve your site’s SEO and ensure it remains accessible to every visitor who arrives at your domain.
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