Alt Text Quality

What is alt text quality?

Alt text quality is how well an image’s alt attribute replaces the image for someone who can’t see it—accurate, useful, context-aware, and not stuffed with keywords or filler.

I’ve reviewed enough sites to know this gets misunderstood in two opposite ways. One camp treats alt text like an SEO cheat code. The other treats it like tedious accessibility paperwork. Both miss the point. Good alt text is replacement text. That’s the center of it.

I used to lean too hard toward the SEO angle myself. Years ago, when I was auditing ecommerce pages at scale, I thought adding product keywords into every image alt field was at least a mild ranking win. Then I sat through a debugging session on a store with thousands of product thumbnails and listened to how the experience would sound to a screen reader user: repetitive, noisy, borderline unusable. My mental model was wrong. The best alt text usually helps SEO because it is clear and relevant—not because it smuggles extra keywords into HTML.

That distinction matters.

In practice, high-quality alt text usually does three things:

1. It supports accessibility for screen reader users and people browsing without images.
2. It matches context by describing what matters on that specific page.
3. It avoids spam like keyword stuffing, boilerplate, or made-up AI descriptions.

Google’s image guidance has been fairly consistent on this: write descriptive, useful alt text when it makes sense. The HTML spec frames alt as a text alternative, not a hidden ranking field. If you keep those two ideas in your head, you avoid most mistakes.

Why alt text quality matters

Accessibility comes first

This is the part I don’t like seeing buried under “SEO benefits.” If an image carries meaning, the alt text may be the only way some users get that meaning. W3C’s WAI guidance is clear here: the text alternative should communicate the purpose or content of the image in context.

Bad alt text breaks that handoff. Sometimes quietly.

• A product image with alt="image" says almost nothing.
• A chart with alt="chart" hides the actual takeaway.
• A linked icon with missing alt can make navigation confusing or impossible.

I once looked at a SaaS site where the pricing page used image-based buttons in one old template—yes, one of those legacy sections nobody wanted to touch. The buttons looked fine visually. But the markup exposed either empty alt or filenames. So a key step in the funnel was basically reduced to nonsense for assistive tech users. The SEO issue there was secondary. The usability failure was immediate. (And, honestly, this is where “small technical debt” becomes expensive very fast.)

SEO benefits exist, but they’re smaller than most teams expect

Alt text can help search engines understand images. Google has said as much for years, and in image-heavy verticals that context does matter. But I’d be careful not to oversell it. I’ve never seen alt text alone rescue weak pages.

What I have seen: solid alt text helps when it sits inside a better system—relevant copy, logical headings, crawlable image URLs, sensible filenames, decent performance, and structured data where appropriate. Alt text is one signal among several. Useful. Not magic.

(Quick caveat: if you work on ecommerce or image search-heavy properties, the upside can be more noticeable there than on a text-first B2B blog.)

It exposes whether your publishing process is sloppy

This is an underrated reason to audit it. When a team can’t produce useful alt text, it usually means one of three things: they don’t know why the image is there, the CMS workflow is broken, or no one owns quality control. Sometimes all three.

That’s why alt text quality is a diagnostic signal. Not a perfect one—but a revealing one.

What good alt text looks like

Good alt text is usually:

• Accurate: it describes what’s actually shown.
• Specific: it includes the detail that matters.
• Context-aware: it matches the page’s purpose.
• Concise: no rambling.
• Natural: it sounds like language, not a tag dump.
• Non-redundant: it doesn’t repeat nearby text for no reason.

If a page is about pruning roses, this works:

Gardener pruning rose stems with hand shears in early spring

This does not:

roses gardening pruning flowers garden tips best rose pruning image SEO

The second version sounds like someone panicked and fed a keyword list into a field they hoped Google would reward. I still see versions of this every month.

Short. Useful. Human.

Alt text depends on image type

Not every image should be described the same way. This is where a lot of teams over-standardize and make things worse.

Informative images

If the image carries content, the alt text should communicate that content.

Example: alt="Golden retriever puppy sleeping on a blue sofa"

Functional images

If the image acts as a button or link, describe the action or destination—not the pixels.

Good: alt="Download pricing guide"

Weak: alt="PDF icon"

Decorative images

If the image adds no information and exists for visual styling, an empty alt attribute is often correct:

• alt=""

This is one of those areas where people get nervous and over-describe everything. Don’t. Decorative images should usually be skipped by assistive tech, not narrated. (Edit, mid-thought—assuming they’re actually decorative and not quietly doing content work.)

Complex images

Charts, diagrams, and infographics need more than a label. A short alt text can identify the image, but the real values or takeaway should appear in nearby text, a caption, or a longer description.

Example short alt text: alt="Bar chart comparing organic traffic growth across four quarters"

Then the article should explain what happened in those quarters and why it matters.

Real-world example

On a Shopify store we worked with, the collection pages had a messy pattern: many product images inherited near-identical alt text from product titles, some decorative badges had keyword-heavy alt values, and a few promotional banners had empty alt despite carrying offer details. It was a classic “nobody designed the workflow” situation.

We didn’t start by rewriting everything. That would have been slow and expensive. Instead, I sampled templates and asked three questions: which images are meaningful, which are functional, and which are decorative? Once we separated those, the rewrite got easier.

The biggest improvements came from fixing the product gallery template and the linked promotional graphics. Not because Google suddenly showered the site with rankings, but because the markup became coherent. The alt text stopped fighting the page. Screen reader output became less repetitive. Internal QA got simpler. And the SEO side benefited in the boring way good systems often do—clearer inputs, fewer weird edge cases, less junk at scale.

I used to think scale meant automation first. Now I think classification first, automation second. That changed how I approach audits.

Signs of poor alt text quality

You likely have a problem if your site is full of examples like:

• alt="image"
• alt="photo"
• alt="screenshot"
• alt="keyword, keyword, keyword"
• filename leftovers like alt="IMG_4837"
• the same alt repeated across dozens of different images
• missing alt on meaningful images
• AI-written text that invents people, objects, or actions not present

Most of the time this comes from rushed uploads, brittle CMS defaults, or bulk automation. Not malice. Just process drift.

How to evaluate alt text quality

Here’s the framework I use.

1. If the image vanished, would the alt text replace it well enough?

This is still the best test I know. Not perfect, but close to the intent of the attribute.

2. Does the wording match what users need on this page?

A category page needs product-identifying details. A tutorial needs action-focused description. A news page may need the subject and event. Context changes the right answer.

3. Is it redundant with nearby copy?

If the caption already explains the image in full, the alt text may only need a shorter equivalent. Repetition adds noise.

4. Does it sound like it was written for a person?

If it sounds like hidden metadata, rewrite it.

5. Are you reviewing the templates that create most of the problem?

Start with high-impact areas:

• product listing templates
• article hero image components
• ecommerce galleries
• image links in navigation
• CMS media library defaults

Template-first audits win faster. Usually by a lot.

Decision tree: what should this image’s alt text be?

1. Is the image purely decorative?
   Yes → use alt="".
   No → go to step 2.
2. Does the image function as a link or button?
   Yes → describe the action or destination.
   No → go to step 3.
3. Does the image contain important information?
   Yes → describe the meaningful content in context.
   No → go to step 4.
4. Is it a complex chart, infographic, or diagram?
   Yes → write short alt text and provide the full explanation nearby.
   No → go to step 5.
5. Would your current alt text sound reasonable if read aloud in the page flow?
   Yes → keep it.
   No → rewrite for clarity and brevity.

How to audit alt text quality

I usually combine crawling, segmentation, and manual review.

Useful tools:

• Screaming Frog SEO Spider for exporting image URLs and alt attributes at scale
• Google Search Console for watching image search trends
• browser dev tools or CMS exports for template inspection
• WAVE or Axe for accessibility checks around image markup

A practical process:

1. Crawl the site and export image alt data.
2. Segment by template or content type.
3. Flag missing, duplicate, empty, overlong, and stuffed entries.
4. Manually review samples from each section.
5. Prioritize pages where images drive comprehension or conversions.
6. Fix the workflow so new bad alt text stops appearing…

Common mistakes

• Treating alt text as a keyword field instead of replacement text.
• Describing everything, including decorative images that should use empty alt.
• Ignoring function on linked images and buttons.
• Repeating captions verbatim when a shorter alt would do.
• Using AI drafts without review, especially on high-traffic templates.
• Applying one rule to every image type.
• Fixing isolated pages manually while leaving the broken template untouched.

Self-check

Before publishing, I’d ask:

• Is this image informative, functional, decorative, or complex?
• If informative, did I describe what matters on this page?
• If functional, did I describe the action instead of the appearance?
• If decorative, did I leave alt="" rather than forcing text?
• Does the alt sound natural when read aloud?
• Did I avoid stuffing keywords or repeating nearby copy?
• If AI generated the draft, did a human verify accuracy and context?

FAQ

Does alt text help SEO?

Yes, it can help search engines understand images and sometimes reinforce page relevance. But I wouldn’t treat it as a major standalone ranking lever.

Should every image have alt text?

Every image should have an alt attribute decision. Meaningful images need descriptive alt. Decorative images often need empty alt.

Is empty alt the same as missing alt?

No. Empty alt (alt="") tells assistive tech to skip a decorative image. Missing alt leaves ambiguity and is usually worse.

How long should alt text be?

As long as needed, and no longer. I don’t optimize for a magic character count. I optimize for usefulness and clarity.

Should I include keywords in alt text?

Only if they fit naturally and accurately. If you have to force them, leave them out.

Can AI write alt text for me?

It can draft it. It should not be blindly trusted. AI often misses page context or invents details. (I should mention—we tried broad automation on this before, and the review queue got ugly fast.)

What’s the biggest alt text mistake on ecommerce sites?

Usually template-generated repetition: every product image gets near-identical alt, while banners, badges, and linked graphics are handled inconsistently.

How do I prioritize fixes on a large site?

Start with templates that affect the most pages and the most meaningful images. Don’t begin with random one-off fixes.

Bottom line

Alt text quality is mainly about accessibility, with SEO upside as a side effect of clarity. The best alt text is accurate, specific, contextual, and restrained. If it sounds useful when read aloud in the page flow, you’re probably close. If it sounds like hidden metadata, you’re not.

When I need to sanity-check my own thinking here, I go back to Google Search Central’s image guidance, W3C WAI recommendations, and the HTML spec. Not because they make the work exciting—but because they keep you from inventing clever rules that break the obvious thing: helping people understand the image.