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HTML images contain no text

Description

This rule checks that images of text are not used

Applicability

This rule applies to any image resources rendered in a web page.

Expectation

Each test target has no visible text, except if at least one of the following is true:

Assumptions

Accessibility Support

There are no accessibility support issues known.

Background

This rule is designed specifically for SC 1.4.5 Images of Text. There are however only minimal differences between this criterion and SC 1.4.9 Images of Text (No Exception). The two differences are that customizable images of text are allowed, and that images of text are allowed when the presentation cannot otherwise be achieved. These scenarios are so rare the rule ignores them as part of the assumptions, and so the accessibility requirements mapping of these two criteria is the same.

Bibliography

Accessibility Requirements Mapping

Input Aspects

The following aspects are required in using this rule.

Test Cases

Passed

Passed Example 1

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This image resource referenced by the img element does not contain text.

<img src="/test-assets/shared/fireworks.jpg" alt="fireworks going off behind the Eiffel tower at night" />

Passed Example 2

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This image resource referenced by the input element does not contain text.

<input type="image" src="/test-assets/shared/file.svg" alt="New file" />

Passed Example 3

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This image resource referenced by the svg element does not contain text.

<svg width="2in" height="3in" xmlns="http://www.w3.org/2000/svg">
	<image x="20" y="20" width="200px" height="100px" href="/test-assets/shared/fireworks.jpg">
		<title>Fireworks in Paris</title>
	</image>
</svg>

Passed Example 4

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This image resource referenced by the object element contains text, but it is not the most significant content.

<object data="/test-assets/0va7u6/times_square.jpg" title="Picture of Times Square, New York"></object>

Passed Example 5

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This image resource referenced by the img element contains text, but its presentation is essential to convey the information.

<p>
	The following image is a close up of the cover of a Classic Comics book titled "Ivanhoe" illustrating a font that
	looks like an old Gothic style font.
</p>
<img
	src="/test-assets/0va7u6/ivanhoe.png"
	alt="The word Ivanhoe written in a style that resembles old medieval letters. The letter I is colored to resemble copper. The remaining letters are black. The background is yellow."
/>

Passed Example 6

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This image resource referenced by the background-image property of the div element contains a logo with text. Logotypes are considered an essential exception.

<div
	role="img"
	aria-label="W3C logo"
	style="
    width: 100px;
    height: 100px;
    background-image: url(/test-assets/shared/w3c-logo.png);
    background-repeat: no-repeat;
  "
></div>

Passed Example 7

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This image resource referenced by the img element is an image of text (the book covers), but it is just meant to decorate the webpage of a book store, therefore it is decorative.

<img src="/test-assets/0va7u6/books.jpg" alt="" />
<p>Welcome to my book store</p>

Passed Example 8

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These image resources referenced by the input elements are images of text (the letter “A”), but they are not expressing anything in a human language. The image is only used to indicate how the font size can be controlled.

<input
	type="image"
	src="/test-assets/0va7u6/smallA.png"
	style="border: 1px solid black;"
	width="50px"
	height="50px"
	alt="Decrease text size"
/>
<input
	type="image"
	src="/test-assets/0va7u6/bigA.png"
	style="border: 1px solid black;"
	width="50px"
	height="50px"
	alt="Increase text size"
/>

Failed

Failed Example 1

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This image resource referenced by the img element contains text for which the particular presentation is not essential.

<img
	src="/test-assets/0va7u6/textimage.jpg"
	alt="The Accessibility Conformance Testing (ACT) Rules Format 1.0 defines a format for writing accessibility test rules."
/>

Failed Example 2

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This image resource referenced by the input element in the Image Button contains text for which the particular presentation is not essential.

<input type="image" src="/test-assets/0va7u6/button.jpg" alt="Press me" />

Failed Example 3

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This image resource referenced by the background-image property of the div element contains text for which the particular presentation is not essential.

<div style="background-image: url(/test-assets/0va7u6/textimage.jpg); width: 500px; height: 200px;" />

Failed Example 4

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This image resource referenced by the img element contains text that provides redundant information, but it still is information, therefore it is not decorative.

<img src="/test-assets/0va7u6/welcome.png" alt="" />
<p>Welcome to our website</p>

Failed Example 5

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This img element loads an SVG with text as an image resource. Because the SVG is loaded as an image resource, instead of being embedded in HTML the text cannot be selected or customized.

<img
	alt="WCAG Rocks"
	src="data:image/svg+xml;utf8,
<svg xmlns='http://www.w3.org/2000/svg' height='20px' width='80px'>
  <text x='0' y='15'>WCAG Rocks</text>
</svg>"
/>

Inapplicable

Inapplicable Example 1

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The resource referenced by the object element does not have visible pixels.

<object date="/test-assets/0va7u6/textimage.jpg" style="display: none"></object>

Inapplicable Example 2

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This svg element does not have image element descendants.

<svg xmlns="http://www.w3.org/2000/svg">
	<text x="20" y="35">My</text>
	<text x="45" y="35">cat</text>
	<text x="55" y="55">is</text>
	<text x="70" y="55">Grumpy!</text>
</svg>

Glossary

Attribute value

The attribute value of a content attribute set on an HTML element is the value that the attribute gets after being parsed and computed according to specifications. It may differ from the value that is actually written in the HTML code due to trimming whitespace or non-digits characters, default values, or case-insensitivity.

Some notable case of attribute value, among others:

This list is not exhaustive, and only serves as an illustration for some of the most common cases.

The attribute value of an IDL attribute is the value returned on getting it. Note that when an IDL attribute reflects a content attribute, they have the same attribute value.

Embedded Image

An element presents an embedded image when any of the following is true:

Essential text presentation

The presentation of text is considered essential in one of more of the following scenarios:

  1. The text and its presentation is part of a brand; or
  2. The text is part of a digitized image of a physical object; or
  3. The text is part of a free-form digital illustration; or
  4. The text is part of an image with other graphical objects, where its relationship is informative; or
  5. Changing part of the presentation would alter the meaning of content on the page.

Examples of text for which the presentation is essential include:

  1. Logos, product names, or slogans
  2. Image of a hand-written letter, picture of a street sign, or a scanned contract
  3. A digital signature, or a note written using a stylus,
  4. A bar chart, diagram, or maps with place names
  5. An image showing a font, or showing the difference between font-weights

Note: WCAG includes a generic definition of “essential”.

Insignificant

Content that is neither purely decorative, nor required for understanding the purpose of certain pieces of information or functionality. Insignificant content is often used to provide context.

Example: A picture of New York’s Time Square may include taxis, a famous pizza restaurant, and theater advertisements, etc. None of these are purely decorative. They provide clues as to where the picture was taken. But neither are any of these required to understand the picture as a whole. Even if the picture itself is significant, the taxis in the picture are not.

Outcome

An outcome is a conclusion that comes from evaluating an ACT Rule on a test subject or one of its constituent test target. An outcome can be one of the three following types:

Note: A rule has one passed or failed outcome for every test target. When there are no test targets the rule has one inapplicable outcome. This means that each test subject will have one or more outcomes.

Note: Implementations using the EARL10-Schema can express the outcome with the outcome property. In addition to passed, failed and inapplicable, EARL 1.0 also defined an incomplete outcome. While this cannot be the outcome of an ACT Rule when applied in its entirety, it often happens that rules are only partially evaluated. For example, when applicability was automated, but the expectations have to be evaluated manually. Such “interim” results can be expressed with the incomplete outcome.

Rendered Image Resource

A rendered image resource in a web page is any resource with visible pixels that has been specified in the list of image sources of an embedded image.

Visible

Content perceivable through sight.

Content is considered visible if making it fully transparent would result in a difference in the pixels rendered for any part of the document that is currently within the viewport or can be brought into the viewport via scrolling.

Content is defined in WCAG.

For more details, see examples of visible.

Web page (HTML)

An HTML web page is the set of all fully active documents which share the same top-level browsing context.

Note: Nesting of browsing context mostly happens with iframe and object. Thus a web page will most of the time be a “top-level” document and all its iframe and object (recursively).

Note: Web pages as defined by WCAG are not restricted to the HTML technology but can also include, e.g., PDF or DOCX documents.

Note: Although web pages as defined here are sets of documents (and do not contain other kind of nodes), one can abusively write that any node is “in a web page” if it is a shadow-including descendant of a document that is part of that web page.

Rule Versions

  1. Latest version, 20 December 2023

Implementations

This section is not part of the official rule. It is populated dynamically and not accounted for in the change history or the last modified date.

Implementation Type Consistency Report
Trusted Tester 5.1 Test methodology Partial Trusted Tester Report
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