Kilotest: Diagnoses of sizes attribute invalid violation by HTML element 581 on National Coalition Against Censorship page

Basics

About the page

• URL: https://ncac.org/
• Tested 3 days ago on 2026-10-07 at 21:59 by job 261007T2138-qpt
• Summary of results:
  • Rule engines:
    • Called: 12
    • Were able to test: 12
    • Reported any rule violations: 11
  • Violations: 619
  • Violators: 284
  • Issues: 49
• Download the full technical report (JSON)

About the issue

• Why it matters: Item behaves improperly
• Priority: highest
• Related WCAG standard: 1.3.1
• Reported by 1 rule engine (Html Checker)
• Violations: 2
• Violators: 2

About the violator

• Tag name: IMG
• Text: [not applicable]
• Start tag: <img src="https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px.jpg" class="disable-lazyload ls-img-layer ls-layer" alt="" decoding="async" fetchpriority="high" style="left: 0px; top: 0px; margin: 0px; z-index: auto; width: 1100px; height: 450px; padding: 0px; border-width: 0px; border-radius: 0px; font-size: 36px;" srcset="https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px-200x82.jpg 200w, https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px-300x123.jpg 300w, https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px-400x164.jpg 400w, https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px-530x217.jpg 530w, https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px-600x245.jpg 600w, https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px-768x314.jpg 768w, https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px-800x327.jpg 800w, https://ncac.org/wp-content/uploads/2026/09/Copy-of-Gala-Hero-Image-2026-1200-x-300-px.jpg 1100w" data-ls-slidein="1" data-ls-slideout="1" data-ls-layer-id="1" data-ls-active="">
• XPath: /html/body/div[2]/div[1]/div[2]/div[1]/div[1]/div[1]/div[1]/div[1]/div[2]/div[3]/div[1]/img[1]
• Bounding box: x = 410, y = 190, width = 1100, height = 450
• Reported by Html Checker

Diagnoses

Here is how rule engines diagnose the sizes attribute invalid issue for HTML element 581 of the National Coalition Against Censorship page.

1. When the srcset attribute has any image candidate string with a width descriptor, the sizes attribute must also be specified.

   Rule engine: Html Checker (World Wide Web Consortium)