How to Write Alt Text for Images To Improve SEO & Accessibility

How to Write Alt Text for Better SEO & Accessibility

Alt text might seem like a small task, but it can transform how users and search engines perceive your website. Alt text, short for “alternative text,” helps people with visual impairments understand your images. It also offers a searchable descriptor for search engines. In this post, we’ll look at practical ways to write alt text to help users and aid small businesses and organisations in standing out online.

Why Alt Text Matters

Whether you run a boutique clothing store or manage a nonprofit’s website, proper alt text ensures everyone can engage with your content. It also tells search engines that your images match relevant queries. Here’s how it works in two main areas:

• Improving Accessibility. Screen readers read out alt text for visitors who cannot see images. This means a well-written description can be the difference between a visitor feeling involved or left out. The right alt text should describe the image’s content or function clearly. When alt text is missing or vague, those using assistive technologies miss essential information.
• Boosting SEO and Visibility. Search engines rely on text clues (particularly alt attributes) to figure out what an image contains. Descriptive alt text can enhance the likelihood that your images show up in image-based search results. That increased visibility can attract people searching for exactly what you offer. Well-structured alt text strengthens your site’s overall optimisation strategy. For more ideas on climbing search rankings, you can check out our 10 SEO Tips.

Alt text is vital for meeting Web Content Accessibility Guidelines. If you’re new to these standards, our Beginner’s Guide to WCAG covers the basics in a straightforward way.

Key Guidelines for Writing Alt Text

Deciding what to write in alt attributes can feel confusing at first. The challenge is to add text that conveys the image’s content, whilst also remaining concise and accurate.

1. Descriptive, Yet Concise. A sentence or short phrase is usually enough. Long paragraphs can overwhelm screen reader users. For instance, instead of writing “A photo of our new eco-friendly cotton t-shirt line displayed against a lush green background, featuring bright lighting and multiple angles,” it may work better to say “Our eco-friendly cotton t-shirts displayed on a simple green background.” Short and meaningful descriptions suit accessibility needs and search engines.
2. Contextual Relevance. Ask yourself, “What purpose does this image serve on the page?” If it’s an infographic about quarterly sales, the alt text should convey that data (e.g., “Bar graph showing a 10% sales increase in the second quarter”). Context helps users link the image’s content to the broader topic. If the image is purely decorative, like a page divider, you can use an empty alt attribute (alt="") so screen readers skip it.
3. Avoid Overstuffing Keywords. Search engines value natural language. Adding a stream of keywords might hurt your rankings and frustrate anyone listening through a screen reader. erms, but keep the description logical and user-friendly.

Tips and Tools for Implementation

So, how do you put these guidelines into practice? Here are a few steps to try:

1. First, you can perform a quick audit to see where you stand. Web development systems such as Wordpress and Webflow offer tools or plugins to find images missing alt attributes, and tooling such as WAVE will flag missing alt text. Once you spot them, create short but meaningful descriptions for each.
2. For large sites, an example approach is using a site crawler like Screaming Frog to export a list of all images. Then, check each for relevant alt attributes. This process can highlight patterns. For example, perhaps your product galleries lack alt text.

Common Mistakes to Avoid

Writing alt text is straightforward, but there are pitfalls to watch out for:

• Generic Descriptions. Saying “photo of person” or “image of table” gives minimal context. Readers and search engines lose out on real meaning.
• Leaving Fields Blank. Some site owners skip alt text entirely. This alienates visually impaired visitors and leaves search engines guessing.
• Repeating ‘Image of…’. Screen readers already communicate that an image is present, so focus on content and purpose.
• Overusing Keywords. Jamming your alt text with a list of search terms is actually bad for SEO. Keep it natural and relevant.

Looking Ahead

Generative AI, such as LLMs, is opening doors to automated image labelling, but automated tools sometimes misinterpret images. These tools can save time, but human review is still essential to ensure accuracy. I think an interesting approach would be for automated tools to use this technology to flag poor alt text.

Additionally, voice search is on the rise. As more people ask devices like smartphones or smart speakers to find information, well-written alt text could help your images appear in relevant voice-driven results.

Lastly, Generative Engine Optimisation (GEO) is becoming more of an importance, as people switch to using ChatGPT and Perplexity for searching. Alt text could be the nudge you need to be included in generative AI results. If you’re serious about future-proofing your site, paying attention to alt text now sets you up for success later.

Final Thoughts

Alt text writing isn’t just for compliance. It’s a tool for better user connections and improved search rankings. By describing images in a clear, precise way, you welcome visitors who rely on assistive technology and guide search engines to your content. This strategy can enhance your site’s performance without feeling heavy-handed or overly technical.

If you’re looking to boost your efforts, consider reviewing Siteimprove’s guide for step-by-step instructions or checking out the resources on AccessiblyApp for more best practices. A few minutes spent refining each alt attribute can have a long-lasting effect on your site’s user experience and visibility.

Small businesses and organisations have a lot to gain from good alt text. You could start by auditing a handful of key pages (like your homepage and top product listings) and gradually expand from there. If you need further help, or an audit of your website, our team provides accessible web development and auditing services to help you refine your site for all users, and boost your search rankings.