Audit of 306,634 Images on the Web's 10,000 Most-Visited Homepages: One in Nine Has No Alt Attribute at All

37% of the sites audited ship at least one homepage image with no alt attribute. Only one in four describes every image on its homepage.

NEW YORK, NY, UNITED STATES, August 11, 2026 /EINPresswire.com/ -- Alt text has been an accessibility requirement for nearly three decades, and it has quietly become a visibility requirement too: AI assistants and AI-augmented search engines read image descriptions when deciding what a page contains and whether to cite it. A new crawl study suggests the web's most successful sites have not caught up with either audience.

In July 2026, ImageSEO, an image-optimization service for WordPress sites, crawled the 10,000 highest-traffic domains on the public Tranco ranking and analyzed every image tag on each reachable homepage — 6,162 homepages, 5,306 of them carrying images, 306,634 image tags in total. The crawl covered homepages only, on a single day, parsing the HTML each site served without executing JavaScript — so images injected by scripts are not counted, making the figures conservative on volume. The full methodology, per-category results and raw dataset are published at https://imageseo.io/alt-text-study/.

The headline finding: 34,684 of those images — 11.3 percent, roughly one in nine — carry no alt attribute at all. That is the defect class, and it is not confined to a careless minority: 1,966 of the 5,306 audited homepages — 37.1 percent — ship at least one attribute-less image. Only 24.3 percent of sites carry descriptive alt text on every homepage image, and the median audited homepage describes 77 percent of its images. At the bottom of the distribution, 3.8 percent of these leading sites have no alt attribute on any homepage image at all.

The study is deliberately conservative about what counts as a failure. An empty alt attribute — alt="" — is valid markup that tells assistive technology an image is decorative, and 21 percent of the images audited use it. Those were counted separately, not as defects. Descriptive text was found on 67.7 percent of images. Only the complete absence of the attribute, which leaves screen readers guessing and machines with nothing to read, was counted against a site.

"The surprise isn't sloppiness at the fringes of the web — it's the gaps at the very top," said the ImageSEO team. "These are the most-visited pages in the world, and one image in nine on them is invisible to a screen reader and mute to an AI engine. Alt text used to be the accessibility box nobody checked. Now the machines deciding what to recommend are reading the same field, and most of the web's front pages still have holes in it."

The mechanics behind the gap are familiar to anyone who manages a large media library: alt text is written by hand, image by image, and libraries grow faster than anyone writes. ImageSEO exists for exactly that gap — more than 22,000 accounts have registered since 2019, close to 9,500 websites have been connected to the service, and its current generation pipeline has written more than 55,000 image descriptions since May 2024. Its WordPress plugin, listed on WordPress.org since 2018, has been downloaded more than 94,000 times.

The full dataset — including per-site coverage distributions, the crawl methodology, and the raw CSV — is available at https://imageseo.io/alt-text-study/. ImageSEO is at https://imageseo.io.

About ImageSEO

ImageSEO automates image alt text, filenames and metadata for websites via a WordPress plugin and an API. It has been cited in image-optimization guides across the WordPress ecosystem and processes images for customers worldwide.

Media contact:

Media Relations, ImageSEO

contact@imageseo.io

Media Relations
ImageSEO
contact@imageseo.io

1 in 9 Images on the Web’s Top Sites Has No Alt Text (We Checked 306,634)