Missing alt text is both an SEO risk and a legal-compliance risk under WCAG 2.2, ADA, and the European Accessibility Act 2025. Image search referrals on commercial sites typically account for 5–15 percent of organic traffic — and that traffic is built almost entirely on alt text and surrounding context. A clean alt-attribute audit pays back twice: search visibility and compliance posture.
Step 1. Run the Image Audit
Site → Image Audit scans every parsed page and records:
- All
<img>tags discovered. altattribute value — empty, missing, or valid.- File size and dimensions.
- Presence of
loading="lazy".
Step 2. Three filters that surface most issues
- Missing alt attribute entirely — highest priority, WCAG fail.
- Empty alt (
alt="") — acceptable for decorative images, never for content images. - Generic alt (
alt="image",alt="photo") — as harmful as missing alt.
Step 3. Weight by page traffic
Connect GSC and sort image-alt issues by the host page's organic sessions. The top-trafficked pages drive most of the recoverable image-search opportunity. Fix those first; let the long tail wait for batch passes.
Step 4. Export and write better alt text
Export to XLSX with columns: page, image URL, current alt, suggested alt. Brief your content team with three rules:
- Describe the image; do not transcribe its filename.
- Include relevant keywords naturally; never stuff them.
- 8–12 words for content images;
alt=""for purely decorative images.
Three CMS patterns that produce alt regressions
- CMS auto-generating alt from filename —
IMG_20240515.jpgbecomesalt="IMG 20240515": worthless. - Same alt across all product variants — describe what is different (color, angle, scene) per variant.
- Keyword-stuffed alt — Google treats this as spam; harms rankings rather than helping.
The CLS connection
Image audits also surface a Core Web Vitals risk: images without width and height attributes
cause Cumulative Layout Shift during render.
The 2-UA image audit flags missing dimensions alongside missing alt, so one workflow fixes two ranking signals.
Use the free SEO page audit for a quick single-page check, or run continuous image audits inside any 2-UA project.