Skip 1x1 tracking pixels with empty alt in img_alt_empty_check

[Copilot]

The img_alt_empty_check rule incorrectly flags 1×1 tracking pixels with alt="" as WCAG 1.1.1 violations. These are not meaningful visual content and should be treated as decorative no-ops.

Changes

• src/pageScanner/checks/img-alt-empty-check.js

  • Added isTrackingPixel(node) helper that detects 1×1 pixels via:
    • HTML width="1" + height="1" attributes (any src, including base64)
    • Computed naturalWidth === 1 + naturalHeight === 1 for loaded images without explicit size attributes
  • evaluate() now returns early (true) when hasEmptyAlt && isTrackingPixel(node)

• tests/jest/rules/imgAltEmpty.test.js — new cases:

  • <img src="track.gif" alt="" width="1" height="1"> → pass
  • <img src="https://example.com/whatever.png" alt="" width="1" height="1"> → pass
  • <img src="tiny.png" alt="" width="2" height="1"> → fail (not 1×1)
  • <img src="maybe-tracker.gif" alt=""> → fail (no dimension attributes to confirm)

function isTrackingPixel( node ) {
    const widthAttr = node.getAttribute( 'width' );
    const heightAttr = node.getAttribute( 'height' );
    if ( widthAttr === '1' && heightAttr === '1' ) {
        return true;
    }
    if (
        typeof node.naturalWidth === 'number' &&
        typeof node.naturalHeight === 'number' &&
        node.naturalWidth === 1 &&
        node.naturalHeight === 1
    ) {
        return true;
    }
    return false;
}

Fixes PRO-775

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Limit tracking-pixel skip to img elements

The img_alt_empty selector also runs this check for input[type="image"][alt=""], so this new exception makes a 1×1 image submit button such as <input type="image" alt="" width="1" height="1"> pass. Unlike passive tracking pixels, image inputs are controls and still need a non-empty accessible name; the existing tests already expect empty-alt image inputs to be violations, but this dimension-based bypass now lets those violations through when the control is 1×1.

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[SteveJonesDev]

Code Review Notes

Reviewed this PR against issue #1660 — the implementation looks correct.

What's working well:

• isTrackingPixel() helper correctly checks both HTML width/height attributes and naturalWidth/naturalHeight for loaded images without explicit attributes
• The early return is slotted in cleanly before the existing return !hasEmptyAlt line, leaving all other existing skip conditions untouched
• All 4 test cases specified in the issue are present and correctly asserted

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@pattonwebz this is otherwise ready for human review, can you resolve the merge conflict with develop?