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alt text

27 established claims - 13 refused by the grounding gate

Verdict

As of Google's March 2026 image SEO documentation, alt text is the most important attribute for providing image metadata, Google uses it with computer vision algorithms and page content to understand image subject matter, and keyword stuffing in alt attributes may cause a site to be seen as spam; Google Search Essentials as of December 2025 also lists alt text among descriptive locations where site owners should place words people would use to look for content. A 2020 Google statement reported by Search Engine Journal in 2023 said that if you did not care about Image Search you would not really need to worry about alt text from a Search point of view, and its ranking factors entry states that alt text is a confirmed ranking factor for image search only and not a Google Search ranking factor. In WebAIM's February 2026 analysis of the top 1,000,000 home pages, 16.2% of home page images had missing alternative text, an average of 10.8 per page, and 10.8% of images with alternative text had questionable or repetitive alternative text.

Written from the 27 established claims below, then checked against them. How that works.

Documented position13

What the operator of the system says in its own documentation.

Google's image SEO best practices documentation states that alt text is the most important attribute when it comes to providing more metadata for an image.

first-party
1 quote from 1 source
The most important attribute when it comes to providing more metadata for an image is the alt text (text that describes an image), which also improves accessibility for people who can't see images on web pages, including users who use screen readers or have low-bandwidth connections.

Google's image SEO best practices documentation states that Google uses alt text along with computer vision algorithms and the contents of the page to understand the subject matter of an image.

first-party
1 quote from 1 source
Google uses alt text along with computer vision algorithms and the contents of the page to understand the subject matter of the image.

Google's image SEO best practices documentation warns that filling alt attributes with keywords…

  • results in a negative user experience.
  • may cause a site to be seen as spam.
first-party
1 quote from 1 source
Avoid filling alt attributes with keywords (also known as keyword stuffing) as it results in a negative user experience and may cause your site to be seen as spam.

Google's image SEO best practices documentation gives…

  • "Dalmatian puppy playing fetch" as its best example of alt text for an image of a puppy.
  • "puppy" as merely better for alt text for an image of a puppy.
first-party
2 quotes from 1 source
Better: <img src="puppy.jpg" alt="puppy"/>
Best: <img src="puppy.jpg" alt="Dalmatian puppy playing fetch"/>

Google's image SEO best practices documentation states that…

  • the alt attribute is used on img elements.
  • for inline SVG elements, site owners can use the title element, in contrast to the alt attribute used on img elements.
first-party
1 quote from 1 source
For the <img> element, you can add the alt attribute of the element, while for inline <svg> elements, you can use the <title> element.
  • Google Search Essentials lists alt text among the descriptive locations where site owners should place the words people would use to look for their content.
  • Google Search Essentials identifies alt text as one of its key best practices.
first-party
2 quotes from 1 source
Key best practices
Use words that people would use to look for your content, and place those words in prominent locations on the page, such as the title and main heading of a page, and other descriptive locations such as alt text and link text.

Search Engine Journal published a statement attributed to Google Search Advocate John Mueller that if you did not care about Image Search, from a Search point of view you would not really need to worry about alt text.

medium confidencetrade press
2 quotes from 1 source
In 2020 , John Mueller, Google Search Advocate, answered a question about the alt text of a quote image during a Google Webmaster Office Hours.
"For Search, what happens with the alt attribute is we use that to better understand the images themselves, in particular, for Image Search. So if you didn't care about Image Search, then from a Search point of view, you don't really need to worry about alt text.

Measured finding8

Something someone actually measured, with the method attached.

In WebAIM's February 2026 analysis of the top 1,000,000 home pages…

  • 16.2% of all home page images had missing alternative text.
  • an average of 10.8 images per home page had missing alternative text.
first-party
2 quotes from 1 source
16.2% of all home page images (10.8 per page on average) had missing alternative text (not counting alt="").
Results below are from February 2026
  • WebAIM's alt text research list of one million home pages was derived from the Tranco ranking.
  • The Tranco ranking, which is the source for WebAIM's alt text research list, combines several sources of top web sites.
first-party
1 quote from 1 source
The million home page list was derived from the Tranco ranking which combines several sources of "top" web sites.
  • WebAIM found that 10.8% of images with alternative text had questionable or repetitive alternative text.
  • Questionable or repetitive alternative text included examples such as alt="image", "graphic", "blank", or a file name.
first-party
1 quote from 1 source
10.8% of images with alternative text had questionable or repetitive alternative text—such as alt="image", "graphic", "blank", a file name, etc., or alternative text identical to adjacent text or the alternative text of an adjacent image.

WebAIM found that the linked images missing alternative text on the top 1,000,000 home pages resulted in links that were not descriptive.

first-party
1 quote from 1 source
45% of the images missing alternative text were linked images—resulting in links that were not descriptive. One out of every four linked images was missing alternative text.

The absence of detected errors in alt text does not indicate that a page is accessible or conformant.

first-party
1 quote from 1 source
All automated tools, including WAVE, have limitations—not all conformance failures can be automatically detected. Absence of detected errors does not indicate that a page is accessible or conformant.

Practical effect2

What is observed to happen in practice, as distinct from what is documented.

Accessibility Checker states that decorative images should use an empty alt attribute rather than being left with no alt attribute at all.

medium confidenceother
1 quote from 1 source
Decorative images should use an empty alt attribute ( alt="" ), not be left with no alt attribute at all.

Accessibility Checker states that alt text is not a magic ranking factor that will instantly move a page to the top of Google.

medium confidenceother
1 quote from 1 source
Alt text is not a magic ranking factor that will instantly move a page to the top of Google. However, it contributes to several signals that search engines use to evaluate content quality and relevance.

Changed on2

A dated change. This is where advice quietly stops being true.

The number of images in WebAIM's measurement of the proportion of images missing alt text grew.

first-party
2 quotes from 1 source
While there were notably more images, the proportion of images missing alt text dropped from 18.5% in 2025.
16.2% of all home page images (10.8 per page on average) had missing alternative text (not counting alt="").

Google's Search Central changelog records that on January 23, 2023, the alt text and filenames in the examples in the Images best practices documentation were updated to be more descriptive.

first-party
3 quotes from 1 source
January 2023
January 23 :
Updated the Images best practices to clarify that Google parses <img> elements (even when they're enclosed in other elements such as <picture> elements) when indexing images. Also updated the alt text and filenames in the examples to be more descriptive.

Echoed without a primary source2

Widely repeated in the field, but traceable only to other repetitions. Listed because knowing something is merely echoed is worth as much as knowing it is documented.

Search Engine Journal's ranking factors entry states that alt text is…

  • a confirmed ranking factor for image search only.
  • definitely not a ranking factor in Google Search.
trade press
2 quotes from 1 source
Alt text is a confirmed ranking factor for image search only. You should craft descriptive, non-spammy alt text to help your images appear in Google Image Search results.
Alt text is definitely not a ranking factor in Google Search. Google has clarified that alt text acts like normal page text in overall search.

Refused13

Claims the research produced that the grounding gate would not accept, with its reason. They are here because a site that only shows what passed gives you no way to judge whether the gate does anything.

Show what was refused

Alt text documentation changed on March 2, 2026, according to Google's Search Central changelog.

Refused: The quotes mention added preferred image metadata and image SEO best practices, but none state that alt text documentation changed.

Unsupported: Alt text documentation

What it rested on
March 2026
March 2
Added preferred image best practices
What : Added a new section on specifying a preferred image with metadata to the image SEO best practices and Discover documentation .

The change to alt text documentation added a new section on specifying a preferred image with metadata to the image SEO best practices and Discover documentation.

Refused: The quotes establish adding a new section on specifying a preferred image with metadata to image SEO and Discover docs, but none mention alt text documentation.

Unsupported: alt text documentation

What it rested on
March 2026
March 2
Added preferred image best practices
What : Added a new section on specifying a preferred image with metadata to the image SEO best practices and Discover documentation .

WebAIM's measurement of the proportion of images missing alt text dropped from 18.5% in 2025 to 16.2% in 2026.

Refused: The quotes support a drop from 18.5% in 2025 to 16.2%, but no cited quote states that the 16.2% figure is for 2026.

Unsupported: in 2026

What it rested on
While there were notably more images, the proportion of images missing alt text dropped from 18.5% in 2025.
16.2% of all home page images (10.8 per page on average) had missing alternative text (not counting alt="").

Alt text is the subject of Accessibility Checker's claim that its analysis of 800 or more websites found that 73.4% experienced an increase in organic traffic after implementing accessibility improvements.

Refused: The cited quote from Accessibility Checker does not mention alt text, only general accessibility improvements.

Unsupported: Alt text is the subject of

What it rested on
Analyzing 800+ websites revealed that 73.4% experienced an increase in organic traffic after implementing accessibility improvements, with the average site seeing a 12% uplift in traffic within three months.

Alt text is the subject of Accessibility Checker's claim that its analysis of 800 or more websites found that the average site saw a 12% uplift in traffic within three months.

Refused: The quote only mentions 'accessibility improvements', not alt text specifically.

Unsupported: Alt text is the subject of

What it rested on
Analyzing 800+ websites revealed that 73.4% experienced an increase in organic traffic after implementing accessibility improvements, with the average site seeing a 12% uplift in traffic within three months.

The alt text states that seoscore.tools asserts that Google Images accounts for 22.6% of all Google searches.

Refused: The cited quote is from a blog post, not from any alt text; no evidence supports the claim about an alt text.

Unsupported: The alt text

What it rested on
Google Images accounts for 22.6% of all Google searches. That is more than YouTube, Google Maps, and Google News combined.

The alt text states that seoscore.tools asserts that Google Images accounts for a larger share of Google searches than YouTube, Google Maps, and Google News combined.

Refused: The cited quote is from a blog post, not an alt text, so it does not establish what the alt text states.

Unsupported: The alt text states

What it rested on
Google Images accounts for 22.6% of all Google searches. That is more than YouTube, Google Maps, and Google News combined.

WebAIM's analysis of alt text in the top 1,000,000 home pages was conducted using the WAVE stand-alone API.

Refused: The quotes establish the evaluation used the WAVE stand-alone API but do not mention alt text, so the specific claim about alt-text analysis is not grounded.

Unsupported: analysis of alt text

What it rested on
The evaluation was conducted using the WAVE stand-alone API (with additional tools to collect site technology and category data).
The WAVE accessibility engine was used to analyze the rendered DOM (Document Object Model) of all pages after scripting and styles were applied.

WebAIM's analysis of alt text in the top 1,000,000 home pages was performed on the rendered DOM of all of the top 1,000,000 home pages after scripting and styles were applied.

Refused: The quotes state the WAVE accessibility engine analyzed the rendered DOM of all pages, but none mentions alt text specifically.

Unsupported: analysis of alt text

What it rested on
The evaluation was conducted using the WAVE stand-alone API (with additional tools to collect site technology and category data).
The WAVE accessibility engine was used to analyze the rendered DOM (Document Object Model) of all pages after scripting and styles were applied.

WebAIM found that missing alternative text for images was detected on 53.1% of the top 1,000,000 home pages.

Refused: The quotes give the issue and 53.1% but do not state the surveyed population of top 1,000,000 home pages.

Unsupported: top 1,000,000 home pages

What it rested on
Missing alternative text for images
53.1%

WebAIM found that 45% of the images missing alternative text on the top 1,000,000 home pages were linked images.

Refused: The quote states the 45% figure but does not specify the top 1,000,000 home pages sample.

Unsupported: on the top 1,000,000 home pages

What it rested on
45% of the images missing alternative text were linked images—resulting in links that were not descriptive. One out of every four linked images was missing alternative text.

All automated accessibility tools including WAVE have limitations for alt text.

Refused: The quote states automated tools including WAVE have general limitations but does not mention alt text specifically.

Unsupported: for alt text

What it rested on
All automated tools, including WAVE, have limitations—not all conformance failures can be automatically detected. Absence of detected errors does not indicate that a page is accessible or conformant.

Not all conformance failures of alt text can be automatically detected.

Refused: The quote only states a general limitation about conformance failures, not specifically alt text failures.

Unsupported: of alt text

What it rested on
All automated tools, including WAVE, have limitations—not all conformance failures can be automatically detected. Absence of detected errors does not indicate that a page is accessible or conformant.