Alt text serves two genuinely distinct audiences at once — screen reader users who need a description of what an image shows, and search engines that can't "see" an image at all without one. This tool scans a page's images and flags which ones are missing this essential attribute.
A single HTML attribute serving both accessibility and SEO
The alt attribute has been part of HTML since its earliest specifications in the mid-1990s, originally conceived primarily as a fallback description for when an image failed to load or for text-only browsers, which were still common in the web's early years. As screen reader technology matured and web accessibility became both a recognized ethical priority and, in many jurisdictions, a legal requirement (governed by standards like the Web Content Accessibility Guidelines), alt text's role as essential accessibility infrastructure became paramount — and separately, search engines have long used alt text as one of their only direct signals for understanding an otherwise "invisible" image's actual content and relevance.
What this tool checks
The tool scans a page's images and identifies which ones are missing alt text entirely, which have alt text that appears too generic or unhelpful (like "image1.jpg" or simply "photo"), and which have alt attributes present at all — providing a quick audit of a page's image accessibility and SEO completeness without needing to manually inspect each image's HTML individually.
Where checking alt text is genuinely important
- Web accessibility compliance — missing alt text is one of the most common and consequential accessibility failures identified in web accessibility audits, directly affecting screen reader users' ability to understand a page's visual content.
- Image SEO and search visibility — properly descriptive alt text helps images appear in Google Images search results and provides context that supports the surrounding page's overall relevance signals.
- Legal and regulatory compliance — many jurisdictions have accessibility requirements for websites, particularly for government, education and larger commercial sites, where missing alt text represents a genuine compliance gap.
- General content quality auditing — as part of a broader technical SEO or content audit, identifying gaps in image documentation across a site.
Frequently asked questions
What makes for good alt text, beyond simply not being empty? Good alt text concisely and accurately describes what the image actually shows and its relevant context, avoiding both being too vague ("image" or "photo") and unnecessarily verbose — it should communicate genuinely useful information to someone who cannot see the image at all, not simply exist to satisfy a technical checklist requirement.
Do decorative images need alt text too? Purely decorative images (that add no informational value) should technically use an empty alt attribute (alt="") rather than being omitted entirely — an empty alt attribute explicitly tells screen readers to skip the image, while a genuinely missing alt attribute can cause some screen readers to read the image's filename aloud instead, a worse experience than intentional silence.
Does keyword-stuffing alt text help SEO? No, and it can actively hurt — Google's guidelines explicitly discourage keyword-stuffed alt text, treating it as a manipulative practice; accurate, genuinely descriptive alt text serves both accessibility and SEO purposes far better than text artificially packed with target keywords unrelated to what the image actually shows.
Further reading
W3C WAI — Images tutorial — The official Web Accessibility Initiative guidance on writing appropriate alt text for different image types.
Google Search Central — Image SEO best practices — Google's guidance on alt text and image SEO, including guidance against keyword stuffing.