Image Alt Test
The Image Alt Text Checker scans every <img> on a webpage and lists which are missing the alt attribute, which have empty alt="", and which have alt text that is too short or non-descriptive. Alt text is the single most important on-page accessibility attribute and a key signal for Google Images search. Pages with strong alt text rank in image search, surface in zero-click visual SERPs, and pass WCAG accessibility audits — three benefits from one cheap fix.
What This Tool Checks
- Total images vs. images with valid alt text
- Images missing the alt attribute entirely
- Images with empty alt="" (decorative declaration)
- Generic alt text ("image", "picture", "photo")
- Alt text length (target 5-15 words)
- Keyword presence in alt text
- Filename used as fallback when alt is missing
Why It Matters for SEO
Alt text serves three audiences: screen readers (accessibility), search engines (Google Images and on-page topical signal), and users on slow connections (alt text shows when an image fails to load). Pages with strong alt text rank well in Google Images — itself a major source of visual-intent traffic — and pass WCAG and ADA audits cleanly. Adding alt text is one of the cheapest, fastest SEO and accessibility improvements available.
How to Fix It
For every content image, add concise descriptive alt text (5-15 words) that describes the image and naturally includes a related keyword if appropriate. For purely decorative images (background patterns, dividers), use alt="" with role="presentation". Update CMS templates so alt is required when uploading new media.
How It Works
We render the page in a headless browser, walk every <img> in the DOM, and read the alt attribute together with the source URL and any nearby caption. Decorative images (correctly alt="" with role="presentation") are scored separately from content images.
Common Mistakes to Avoid
- Missing alt attribute on content images entirely
- Stuffing alt text with keywords ("running shoes cheap buy red running shoes")
- Using filename ("IMG_4823.jpg") as alt text fallback
- Empty alt="" on a content image (correct only for purely decorative images)
- Same alt text across many different images
Quick Checklist
- Every content image has descriptive alt text
- Decorative images use alt="" with role="presentation"
- No filename or "image" used as fallback
- Alt text is 5-15 words, no keyword stuffing
- CMS upload form requires alt text on save