Images drive engagement across the web. Whether you're running an online store, managing a blog, or building a brand site, visuals provide the emotional hook and context that text alone cannot convey.

But there's a small detail within those images that often gets overlooked: alt text.

It sits behind the scenes, invisible to most users. Yet skipping alt text means leaving significant value on the table—both for SEO and user experience. Without it, search engines and screen reader users miss out on essential context about your images.

What Happens When Alt Text Is Missing?

Consider someone using a screen reader like JAWS or VoiceOver. The software reads through your page—headings, paragraphs, links—until it reaches an image. Without alt text, the user hears something like "image" or the raw filename: "IMG underscore 4523 dot jpg." That provides zero useful information.

Search engines face a similar limitation. Googlebot cannot interpret pixels directly. It relies on code, and the alt attribute is the primary way to communicate image content. While Google has improved at inferring image content through machine learning, explicit descriptions still carry more weight than algorithmic guesses.

Proper alt text delivers measurable benefits:

• Accessibility for the 2.2 billion people worldwide with some form of vision impairment
• Visibility in image search results, which account for over 20% of Google searches
• Clearer signals to search engines about your product and content imagery

The challenge? Writing quality descriptions takes time, especially at scale. We'll address that shortly—first, let's define what "good" alt text actually looks like.

(We built AltText.ai to solve this problem, but the fundamentals apply regardless of which approach you use.)

The SEO Case for Alt Text

Google's image understanding has improved significantly through machine learning, but their own documentation reveals where alt text fits in the hierarchy:

Google uses alt text along with computer vision algorithms and the contents of the page to understand the subject matter of images.

Notice the order: alt text comes first. Computer vision assists, but explicit descriptions remain the foundation. Google has grown more sophisticated, yet continues to prioritize what you tell them over what their algorithms infer.

Consider a practical example: a shopper searches for "blue leather messenger bag." Your product photo includes that exact phrase in the alt text. A competitor's image file is named "product-47.jpg" with no description. The search results reflect this difference.

Curious about your site's current state? Our alt text audit checklist can help you assess where you stand.

How to Write Effective Alt Text

With the fundamentals covered, here are the practical guidelines that matter when you're writing alt text in your CMS.

1. Be Descriptive but Concise

Aim for 80-140 characters—roughly the length of a tweet. Screen readers will read longer descriptions, but listener attention tends to fade beyond this range.

For screen reader users, each alt text description interrupts the flow of content. The goal is providing enough information to be useful without becoming a burden. Brief and meaningful beats lengthy and exhaustive.

Consider a red coffee mug on a table. Here are three approaches to describing it:

2. Include Keywords Naturally

Keyword integration is where many sites go wrong. Some ignore keywords entirely. Others stuff descriptions with every possible variation: "coffee mug cup tea drink hot beverage ceramic drinkware buy now best price." Neither approach serves users or search engines well.

Google's algorithms have long since learned to penalize keyword stuffing. More importantly, screen readers must read these descriptions aloud—making stuffed alt text actively hostile to accessibility.

The solution is straightforward: if your target keyword fits naturally, include it. Selling ceramic mugs and targeting that phrase? Write "Red ceramic coffee mug on wooden table." The keyword appears organically within a readable description.

For WordPress users, our WordPress integration automatically incorporates your Yoast or Rank Math focus keyphrase into generated alt text—maintaining natural readability.

3. Write Unique Descriptions for Each Image

A common pattern in site audits: every image labeled "Product image" or simply the brand name repeated across thousands of photos. This wastes an opportunity and provides no useful information to users or search engines.

The principle is simple: different image, different description.

This becomes especially important with product variants. Blue shoe, red shoe, green shoe—each needs distinct alt text. Without unique descriptions, "men's running shoe fire red" and "men's running shoe navy blue" compete for the same generic searches instead of appearing for their specific color queries.

4. Consider Context and Purpose

An important principle that many guides overlook: identical images can require completely different alt text depending on their context.

Consider a stock photo of a smiling family. On a photography portfolio, appropriate alt text might be "Family portrait in natural light, outdoor setting." On a life insurance landing page, the same image might be described as "Young family enjoying time together—the kind of moments worth protecting."

Same photograph, different purpose, different description.

One additional note: purely decorative images—background patterns, visual flourishes, ornamental borders—should use empty alt attributes (alt=""). This signals screen readers to skip these elements entirely, keeping the focus on meaningful content.

5. Addressing Scale Challenges

This is where manual approaches break down. A typical Shopify store might have 5,000 products with four photos each. That's 20,000 images requiring descriptions.

The math reveals the challenge: at 30 seconds per description, 20,000 images requires roughly 167 hours of work—more than a month of full-time effort dedicated solely to writing alt text. For most businesses, this isn't practical.

The takeaway: manual alt text doesn't scale. For high-traffic events like Black Friday, batch processing becomes essential. Our e-commerce holiday prep guide covers the logistics of preparing your catalog efficiently.

6. Maintain Alt Text Over Time

SEO strategies evolve. Products change. Pages are added and removed. Alt text requires ongoing attention to remain effective.

Build a habit of reviewing image descriptions when updating content. Replaced a hero image? Update the alt text. Renamed a product? Ensure the image descriptions reflect the new name. Shifted keyword strategy? Verify that existing alt text aligns with current targets.

Sites that perform well in image search typically aren't employing special techniques—they're simply maintaining their alt text consistently while competitors neglect it.

How AltText.ai Helps

We built AltText.ai to address these challenges. The best practices above apply regardless of which tool you use—or whether you use one at all. But for teams dealing with scale, here's what our platform offers:

AI-powered image analysis generates unique descriptions for each photo—no templates, no generic placeholders. The system supports 130+ languages and integrates directly with WooCommerce and Shopify to incorporate product names. Yoast and Rank Math keywords are pulled automatically.

Additional features include tone controls and prefix/suffix options for brand consistency.

Addressing Backlogs

Many customers come to us with years of accumulated alt text debt—thousands of images with empty description fields, often prompted by a compliance audit or SEO review.

Bulk processing mode handles these backlogs efficiently. Review the generated descriptions, edit any that need adjustment, and regenerate as needed. There are no additional charges for revisions.

Summary

Alt text may seem like a minor detail, but its impact extends further than many realize. Accessibility compliance is increasingly important—and legally required in many contexts. Google image traffic represents a significant opportunity. The 2.2 billion people worldwide with vision impairments deserve access to your content.

Whether you write alt text manually or use automation tools, the key is consistency: stop leaving description fields empty, and stop duplicating the same generic text across your image library.

The goal is straightforward: make your images work harder for both users and search engines.