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SEO and auditingChecked through WebDiag API

Complete Image SEO Audit

Check page images as SEO signals: alt coverage, linked images, empty decorative alt, dimensions, responsive markup, lazy-loading, and social preview image.

  • Alt coverage
  • Linked images
  • PNG/JPEG/WebP
Online tool

Try the tool

Enter a URL: WebDiag will run a safe network check and show the result.

Network check through backend

For HTTP/SEO tools, the URL is sent to the WebDiag API, where SSRF protection, DNS/IP policy, and redirect limits are applied.

Reviewed: 2026-07-17
01

How to use it

  1. 1

    Paste a page URL.

  2. 2

    Run a static HTML scan through the WebDiag API.

  3. 3

    Fix alt, linked images, dimensions, and social preview image by priority.

02

What the tool can do

  • Distinguishes missing alt, empty decorative alt, and linked images without text.
  • Checks width/height, srcset/picture, and loading strategy.
  • Shows og:image and twitter:image as part of image SEO.
03

Common use cases

  • Check a CMS catalog/blog template for image alt text and dimensions.
  • Find linked images without a text equivalent.
  • Check social preview image before publishing a page.
04

How it works inside

H1/alt/png are not split into low-value microtools; alt remains a subcheck inside image SEO.

The check runs on static HTML and safe URL policy.

05

Questions and answers

Why is there no separate Alt Checker?

Because alt is only part of image SEO. A standalone Alt Checker would be a weak microtool.

Is an empty alt always an error?

No. alt='' is correct for decorative images. For linked images, empty alt is usually an accessibility and SEO problem.