Image audit for SEO: fix alt text and dimensions before they hurt rankings

Images are one of the most overlooked SEO signals on a page. Missing alt attributes cost you accessibility and relevance signals. Missing width and height attributes cause layout shifts that hurt Core Web Vitals. Both problems are easy to fix — once you know which pages have them.

Why image attributes matter for SEO

• Alt text helps search engines understand image content and contributes to rankings in image search. Screen readers also depend on it, making it a legal accessibility requirement in many jurisdictions.
• Empty alt (alt="") marks an image as decorative — intentionally invisible to screen readers and search engines. This is correct for icons and spacers, but wrong for content images.
• Width and height attributes allow the browser to reserve space before the image loads, eliminating Cumulative Layout Shift (CLS). CLS is a Core Web Vitals metric that directly affects Google ranking.
• Loading attribute (loading="lazy") defers off-screen images, improving Time to Interactive and Largest Contentful Paint for pages with many images.

What 2-UA tracks per image

For each tracked URL checked with desktop user agent, 2-UA parses all <img> tags and records:

• Total image count
• Images with no alt attribute (missing — SEO and accessibility issue)
• Images with alt="" (empty — intentionally decorative)
• Images with no width or height (potential CLS source)
• The loading attribute value (lazy, eager, or absent)
• The full src URL

How to read the image audit

Open any tracked URL → Quick menu → Image audit. The per-URL view shows:

1. A summary panel: total images, missing alt, empty alt, no dimensions.
2. A row-by-row table of every image with all its attributes.
3. Red Missing badge — no alt attribute at all. Fix immediately.
4. Grey Empty (decorative) badge — alt="". Verify it's truly decorative.
5. Yellow warning on width/height cells — layout shift risk.

The site-wide summary shows all tracked URLs ranked by missing alt count, so you can prioritize the most affected pages first.

Practical fix workflow

1. Use the site-wide summary to identify pages with the highest missing alt counts.
2. Open the per-URL audit table and export the src list to your content team.
3. Add descriptive alt text to content images; set alt="" on decorative ones.
4. Add explicit width and height to all images to eliminate CLS.
5. After deployment, the next content check updates the audit automatically.

Automating this audit means regressions — like a CMS update that strips alt attributes — are caught the next time that page is checked, not months later when rankings drop.