Is it really unnecessary to duplicate visible content in image alt tags?

Why is Google clarifying its stance on alt tags now?

SEO practitioners have long applied an unspoken rule: stuffing alt attributes with keywords under the assumption that each occurrence counts toward ranking. This approach stems from a time when search engines struggled to contextualize images.

Google now has computer vision models capable of analyzing visual content directly. The engine understands that a photo of an Android smartphone on a page discussing "best Android phones 2025" illustrates this topic, even if the alt merely states "Galaxy S25 Ultra front view."

What does it mean that "content is already present elsewhere on the page"?

If your H1 title says "Complete Guide to Internal Linking," and your first paragraph explains what internal linking is, while your image illustrates a link diagram, the alt does not need to repeat "diagram illustrating the complete guide to internal linking."

The alt attribute should provide specific descriptive value to the image itself. In this example, an alt like "diagram showing the hub-and-spoke structure with a central pillar page" is relevant. It describes what the image actually shows, not the general theme of the page.

Does this recommendation apply to all types of images?

The nuance lies in distinguishing between decorative, illustrative, and informative images. A decorative icon can have an empty alt (alt=""). A screenshot showing a Search Console interface must accurately describe what is visible.

For e-commerce product images, it’s different: the alt remains crucial because the image contains the main information. "Nike Pegasus 40 blue running shoe side view" is relevant even if the product title already mentions these elements, as screen reader users need that description.

• Alt text primarily serves accessibility: screen readers read it to visually impaired users
• Google uses the alt as a contextual signal to understand the image, not as a repetition of textual content
• Decorative images should have an empty alt (alt="") to avoid polluting the user experience
• Redundancy harms the experience: a screen reader that reads the same information twice frustrates the user
• Descriptive quality takes precedence over keyword density in alt attributes

Is this statement consistent with field observations?

Yes, and it’s even a welcome confirmation. A/B tests conducted on e-commerce sites show that stuffing the alts with keywords already present in the title and product description does not improve ranking. In contrast, precise and distinctive alt descriptions increase image traffic and CTR.

The real value of a well-written alt is seen in Google Images, where competition is fierce. A recipe site that uses "apple pie" as alt for all its pie photos gets lost in the crowd. One that specifies "caramelized apple pie with nut crumble seen from above" attracts more qualified traffic.

What nuances should be added to this recommendation?

Google doesn’t say that alt is unnecessary; it says duplication is unnecessary. This is a crucial distinction. An empty or generic alt ("image," "photo") remains an SEO mistake. The engine needs to understand what the image represents, especially if the visual content provides complementary information to the text.

Take an article on Core Web Vitals with a PageSpeed Insights screenshot. The text already explains what CWV are. The alt "PageSpeed Insights screenshot showing an LCP of 1.8s and a CLS of 0.05" is relevant because it provides specific data absent from the adjacent text. [To be verified]: Does Google weigh alts containing numerical data differently than generic descriptions? No official documentation confirms this, but observations suggest that it does.

In what cases might this rule not apply?

Websites with very little textual content (portfolios, photo galleries, designer sites) are exceptions. If your page contains only 3 sentences and 12 images, the alt attributes become your main textual surface to contextualize the content. In this case, descriptive and rich alts are essential.

Another case: images containing text (infographics, graphic quotes, annotated diagrams). If your image contains text that Google cannot extract from the DOM, the alt must transcribe it even if this leads to apparent redundancy. A screen reader must be able to access this content.

What should you concretely do with your existing alt texts?

Start with a redundancy audit. Export your alt tags and compare them with the surrounding text content (H1, H2, first paragraph). Tools like Screaming Frog can extract the alts, but relevance analysis remains manual. Look for patterns: alts identical to the title, alts that repeat text verbatim from the content.

Prioritize your high-traffic pages and product sheets. That’s where the impact is measurable. A site with 10,000 images doesn’t need to redo everything in one week, but correcting the top 200 pages can quickly unlock image traffic.

How do you write a good alt that doesn’t duplicate content?

Ask yourself this question: "What do I see in this image that the text does not mention?" For a photo of Ryan Reynolds in an article about Mint Mobile marketing, the text already mentions his name and the brand. The relevant alt would be "Ryan Reynolds holding a Mint Mobile SIM card against a mint green background."

Focus on concrete visual details: angles, colors, actions, composition elements. "Google Search Console interface Coverage tab with red graph showing 127 errors 404" beats "Google Search Console screenshot" in all cases. The former informs, the latter fills.

What mistakes should you avoid when rewriting your alt attributes?

Don't fall into the opposite excess: overly terse alts. "Photo" or "product image" are as useless as an alt that duplicates the title. Aim for 8 to 15 words for an effective descriptive alt. Too short, and you lack precision. Too long, and you risk diluting the information.

Avoid phrases like "image of" or "photo showing." Screen readers already announce that it’s an image. Get straight to the point. "Flow diagram showing Googlebot crawl" becomes simply "Googlebot crawl flow diagram."

• Audit your top 50 pages to identify alts redundant with the text content
• Rewrite the alts to describe what the image actually shows, not the theme of the page
• Maintain empty alts (alt="") for purely decorative images (separators, backgrounds)
• Ensure each informative image has an alt of 8-15 words describing specific visual elements
• Test your pages with a screen reader (NVDA, JAWS) to detect frustrating redundancies
• Document your alt writing rules in your editorial guide to maintain consistency