Alt text just moved from a technical checkbox to a review-stage asset. On October 1, 2026, Google updated its generative AI content guidance and made a manual check “critical” for machine-written image descriptions — including the alt text that can surface in search results. For performance marketers, that means the tiny HTML attribute on an image now carries SEO, accessibility and brand-safety weight.
What alt text actually does
Alt text is a short description attached to an image. When the picture cannot be seen, the words stand in for it: screen readers announce them, browsers show them when a file fails to load, and search engines and AI agents parse them. Google’s own best example is “Dalmatian puppy playing fetch” — a plain description, not a keyword stack.
Browsers also build an accessibility tree, a structured copy of the page used by assistive software. That same tree is now part of how AI agents read a page. If the alt value is empty (alt=””), the image is treated as decorative and skipped. If the attribute is missing, software may fall back to the file name.
The legal and commercial stakes
Alt text is not just a ranking nicety. WCAG success criterion 1.1.1 requires a text alternative for non-text content at Level A, the lowest conformance tier. The European Accessibility Act has applied to e-commerce, banking and other consumer services since June 28, 2025. In the US, accessibility lawsuits are rising: 3,117 were filed in federal court in 2025, up 27% on 2024, according to Seyfarth Shaw.
The gap is still huge. WebAIM’s March 2026 analysis of the top one million home pages found missing alt text on 53.1% of them — down from 68% in 2019, but still more than half the visible web.
Why Google’s update matters
Google’s October 1, 2026 guidance change extends its human-review expectation for AI-generated content to alternate text attached to images. The guidance sets no sampling threshold and requires no record of review, but the instruction is clear: do not ship machine-written descriptions unchecked. That matters because alt text can appear directly in search results, and because AI agents read the same accessibility tree screen readers use.
SEO practitioner Lily Ray has made the same point: design cues carried by alt text and file names need to reach “bots and agents as well.”
Where marketers get it wrong
The most common mistakes cluster around a few patterns:
- Writing for crawlers instead of listeners. Keyword-heavy descriptions read badly and can look like spam.
- Confusing empty and missing. Decorative images should use alt=””, not a file name, “spacer” or a missing attribute.
- Copying visible captions. If alt text repeats the visible caption, screen reader users hear it twice.
- Treating AI output as final. Automation can misread images, and overlay tools promising automatic compliance have drawn regulatory action.
A simple framework to fix it
Use the W3C’s core test: replace the image with its alt text. If the page still makes sense, the description is working. Context decides wording — the same globe image is “International Travel” on a travel site and “International Campuses” on a university site. For linked images, describe the destination. For charts, pair a short alt value with a longer description nearby.
For ad creatives, check the platform. Google Ad Manager offers an optional alt text field for direct-sold image creatives, but programmatic pipes often carry no equivalent. LinkedIn Campaign Manager accepts up to 300 characters, while a 2023 guide found no custom field in Meta Ads Manager or Twitter Ads Manager.
Alt text is now a multi-channel asset: accessibility, search visibility, legal exposure and AI agent readability all meet in one attribute. The brands that treat it as a review step rather than an afterthought will be the ones ready for the next wave of search.
Source: PPC Land
