Why do Alt attributes remain an underutilized SEO tool by most websites?

What does Google really mean by 'clear and concise'?

Google does not provide a specific character limit, but the term 'concise' clearly excludes lengthy descriptions of 200 words. The goal is to convey essential information in a short sentence, typically between 5 and 15 words.

An effective alt describes what the image shows in its editorial context, not a list of keywords. If the image illustrates a process, name that process. If it's a product, provide the brand and model. A simple test: if you read the alt aloud to someone who cannot see the screen, do they understand what is being represented?

Why does Google emphasize user accessibility?

Because screen readers for visually impaired people read alt attributes aloud. An empty alt or ‘image1.jpg’ is not helpful. Google also knows that in some geographic areas or on mobile, images do not always load immediately.

Accessibility is no longer a secondary option: since Core Web Vitals and the focus on user experience, a site that ignores WCAG standards risks not only legal penalties in certain countries but also a decline in perceived quality in Google's eyes. The algorithm crosses various signals, and an accessible site sends a signal of editorial care.

Do alt attributes directly influence the textual ranking of the page?

Yes, but with nuance. The words present in an alt attribute enhance the semantic context of the page for Google. If your article talks about 'link building strategy' and your screenshots have relevant alts mentioning 'backlink', 'anchor', 'link profile', you strengthen the thematic coherence.

However, stuffing an alt with keywords disconnected from the actual image is counterproductive. Google detects the inconsistency between the visual context (via its image recognition AI) and the alt text. Result: at best, you are not rewarded; at worst, you send a spam signal.

• An effective alt describes the image in a short, natural sentence, without keyword stuffing.
• Accessibility (screen readers, slow connections) is a UX criterion that Google indirectly values.
• Words in alts enhance the semantic context of the page and can influence textual ranking if used relevantly.
• Google now combines image recognition and alt text: a blatant inconsistency can be penalizing.
• A site that neglects alts sends a signal of low editorial care, impacting the overall perception of quality.

Is this guideline consistent with what we observe on the ground?

Absolutely. Audits show that sites that care for their alts tend to rank better in image search and achieve significant additional traffic via Google Images. We're talking about 10-20% additional traffic on visually dense sites (e-commerce, photo blogs, recipes, tutorials).

On the flip side, many CMS still generate automatic alts based on the file name ('IMG_1234.jpg'). That's pure noise. SEO teams that invest in manual or semi-automated alt writing using contextual templates see measurable gains, especially on long-tail queries where the image becomes an entry point.

What nuances should we add to this statement?

Google says 'clear and concise' but does not specify if an alt should repeat the H1 title or the introductory text. In practice, avoid strict duplication: if your H1 says 'Optimizing Core Web Vitals', your alt can say 'Graph showing the impact of LCP on conversion rate'. You provide new information.

Another point: decorative images (design icons, separators) should have an empty alt (alt=""), not an absence of attribute. An absent attribute makes screen readers scream; an empty alt tells them 'move along'. Google understands this distinction and does not penalize empty alts on purely decorative items. [To check]: some consultants claim that an excess of decorative images with empty alts can dilute the overall semantic weight of the page, but no public study formally proves that.

When does this rule become secondary?

On purely textual pages (in-depth articles without illustrations), the absence of images is obviously not penalizing. Google does not require images to rank. But as soon as an image is present, its alt becomes expected.

On very technical sites (software documentation, DevOps tutorials), screenshots can be so contextual that a generic alt ('Screenshot of the terminal') adds nothing. In this case, it's better to have a short and factual alt than an attempt at exhaustive description. The balance between real utility and formal compliance remains more of an art than a science.

What should you do concretely on an existing site?

Launch an alt attribute audit using Screaming Frog, Sitebulb, or SEMrush. Export all images and their alts. Sort by categories: empty alts on meaningful images, duplicate alts, too long alts (>150 characters), generic alts ('image', 'photo').

Prioritize strategic pages: product sheets, landing pages, pillar articles. Rewrite alts maintaining a coherent editorial logic. If you manage an e-commerce site with thousands of products, automate using templates incorporating brand + type + key attributes ('Black Nike Air Zoom Pegasus 40 running shoes').

What mistakes should be absolutely avoided?

Do not copy the page title into every alt. It adds nothing and dilutes semantic richness. Do not stuff keywords: 'SEO agency Paris natural referencing consultant' in an alt is pure spam. Google detects it.

Don't forget the images in or

tags: the alt attribute must be on the tag itself, not on the container. And never leave an alt attribute completely absent: at least use alt="" to indicate that it is intentional.

How do you check if your site is compliant?

Use accessibility tools (WAVE, Axe DevTools) that flag images without alt. Run a performance test on a slow connection (throttling in Chrome DevTools) to see what users actually see when images do not load.

Check in Google Search Console, 'Performance' tab, if you are receiving traffic via Google Images. If this traffic increases after optimizing alts, it's a signal of success. Also measure the time spent on the page: relevant alts improve UX, hence dwell time.

• Audit all alt attributes with an SEO crawler and identify images without alt or with generic alt.
• Rewrite alts for strategic pages in a short and descriptive sentence (5-15 words).
• Automate alt generation for high volume sites (e-commerce, directories) using contextual templates.
• Set alt="" for purely decorative images (icons, separators) to avoid cluttering screen readers.
• Check compliance with accessibility tools (WAVE, Axe) and monitor Google Images traffic in Search Console.
• Train editorial teams to integrate alt writing into their publication workflow.

Optimizing alt attributes is seemingly a simple technical task, but it requires editorial rigor and large-scale coherence. On complex or high volume sites, implementing robust automated processes can prove challenging. If you lack internal resources or want to ensure compliance with the latest Google requirements, consulting a specialized SEO agency in accessibility and on-page optimization guarantees controlled deployment and measurable gains quickly.