Image Alt Text for Accessibility — Write Alternative Texts That Boost SEO and Usability

Have you ever browsed a website with broken images? Or worse, have you ever used a screen reader and heard a generic "image" instead of a useful description? Here's the concrete problem: thousands of websites lose visitors and rankings every day because of poorly written alt text or, worse, missing alt text. It's not just a matter of digital etiquette. It's about money. A well-written alt text is not just a WCAG requirement; it's a business card for Google and a better experience for all your users.

We, at Meteora Web, see it every day in the projects that come to us: product galleries without descriptions, decorative banners with kilometer-long texts, incomprehensible infographics. Let's start with a simple principle: a website is measured in revenue, not compliments. If an image doesn't communicate, it's a cost. In this guide, we'll show you how to turn every single image into an asset that works for you.

What is alt text and why is it critical for accessibility and SEO?

The alt attribute (alternative text) is a textual description of an image. It's not visible to normal users, but it's read by screen readers (software that reads page content to people with visual impairments) and search engines. It's your chance to tell Google and your users what the image is about.

Think of it this way: if your website is a storefront, the alt text is the salesperson describing the merchandise to someone who can't see it. A salesperson who says "image" or "photo" isn't doing their job. A salesperson who describes "Red running shoes with a white sole, racing model" is selling. The difference is substantial.

From an SEO perspective, alt text is one of the few on-page elements that lets you tell Google precisely what a photo contains. It's a relevance signal that can drive traffic from Google Images and improve your page rankings. It's precision work that pays twice: accessibility and visibility.

How to write a descriptive alt text that really works?

The golden rule is: describe the content and function of the image, not its existence. Don't write "image of a product" but "Navy blue organic cotton t-shirt with V-neck". You must ask yourself: why is this image here? What should it communicate to someone who can't see it?

Here's an actionable checklist for writing effective alt text:

• Be specific and concise: 125 characters or less. Describe the essentials, not every detail.
• Include the keyword naturally: if the image shows a product, include the product name. Don't force the keyword if it's not relevant.
• Use context: the same photo of a pair of shoes will have a different alt in a product page vs. a fashion article.
• Don't start with "Image of" or "Photo of": it's redundant. The screen reader already announces it's an image.
• End with a period: it helps the screen reader make a natural pause.

Common mistake to avoid: stuffing alt text with random keywords. An alt text like "shoes, buy shoes, shoes online, men's shoes" is spam. Google reads it as such and penalizes. Write for people, not bots.

Decorative images: when to use empty alt and why it's a winning choice?

Not all images need a descriptive alt text. Decorative images (backgrounds, separators, purely aesthetic icons) don't add information to the content. For these, the best choice is an empty alt (alt=""). This tells the screen reader: "skip this image, it's not important".

Why is it a winning choice? Because it avoids creating noise and confusion. Imagine a screen reader user navigating a website and hearing descriptions of every decorative icon: "little blue arrow", "red circle", "gray line". It becomes impossible to follow the thread of the discussion. An empty alt is not an omission; it's a design decision for accessibility.

How to distinguish an informative image from a decorative one?

The question to ask is simple: if I removed this image, would the page content lose meaning? If the answer is no, it's decorative. If the answer is yes, it's informative and deserves a descriptive alt.

Here are some practical examples:

• Decorative: an arrow icon next to a "Learn more" link. The icon adds no information; the link text is already clear. Use alt="".
• Informative: a chart showing sales trends. The chart communicates essential data. Use a descriptive alt or, better, provide the data in an adjacent table.
• Functional: a company logo that, when clicked, leads to the homepage. The alt should be the company name, as it's the label of the link.

Common mistake to avoid: using alt="spacer" or alt="image". These texts serve no one. Either describe accurately, or leave it empty.

How to handle complex images like infographics and charts?

Infographics and charts are the most delicate case. A long, detailed alt text is not the best solution, because the screen reader will read it all in one go, making the experience frustrating. The correct strategy is to split the communication.

The complex image can have a short alt text that summarizes the main concept (e.g., "Infographic showing a 20% increase in online sales in 2025"), but the detail must be provided elsewhere. The options are:

• Adjacent text: write a paragraph below the infographic explaining the key points.
• HTML table: for data, a table is the most accessible format.
• longdesc attribute (deprecated): better to avoid; it's no longer supported.

The practical rule is: alt text gives context, adjacent content gives detail. This way, screen reader users can decide whether to dive deeper or not, without being overwhelmed by a wall of text.

What tools can you use to verify the correctness of alt texts?

You don't need to be an expert to test. Here's a simple and actionable workflow:

• Visual check: open the page in a browser and disable images (or use an extension). If the remaining text makes sense, the alts are well done.
• Screen reader: try navigating the page with a screen reader like NVDA (free) or VoiceOver (built into macOS/iOS). Listen to how images are read.
• Audit tools: use Lighthouse (built into Chrome DevTools) or WAVE to identify images without alt or with unintentional empty alts.

This process gives you immediate feedback. It's not theory; it's daily practice. We do it for our clients, and it works.

What to do now to make your images accessible?

Don't wait for an automated check to flag the problem. Take matters into your own hands. Here are the immediate actions to take:

• Audit existing images: open your most important pages (homepage, product pages, blog posts) and check every alt text. Ask yourself: does it describe the content? Is it useful? Is it empty when it should be descriptive?
• Define an internal rule: establish a company policy. Every informative image must have a descriptive alt; every decorative image must have alt="". Write it down and enforce it.
• Use a CMS that helps you: WordPress has a dedicated field for alt text. Make sure your editors always fill it in. If you use a page builder, verify that the field exists and is visible.
• Train your team: if you work with collaborators, do a 30-minute training session on this topic. It's an investment that pays off in accessibility and SEO.

Remember: accessibility is not a cost; it's an investment. An accessible website works for everyone, ranks better, and avoids legal risks. We, at Meteora Web, work on this every day. If you want a check-up of your site, we know where to start.

To dive deeper into the full picture of web accessibility, read our pillar guide to Web Accessibility WCAG. And if you want to understand how content management ties into strategy, check out how we handle state and APIs to build fluid experiences.