Images - Optimal Content Examples

Introduction

An image is a static two dimensional visual artifact that is a type of non-text content classified as decorative, simple, complex, or an image of text.

Example

Example

Examples

Example

Coding Requirements

The following summarizes selected techniques from the Web Content Accessibility Guidelines (WCAG) 2.0 for satisfying the most common applicable success criteria related to this topic. Additional WCAG 2.0 success criteria, techniques, and failures not listed here may also be applicable depending on the content.

1. Text Description

Decorative Images

Use an empty alt attribute on a decorative image. Do not omit the alt attribute.

For example, <img alt="">.

Source: WCAG 2.0, Technique H67

Simple Images

Provide a short text description in the alt attribute of a simple image.

For example, <img alt="(short text description)">.

Source: WCAG 2.0, Technique H37

Complex Images

Provide all of these items for a complex image:

1. A long text description of the image somewhere in the text of the same page or another page. The long description must include all information and relationships conveyed in the image.

2. A short text summary in the alt attribute of the image.

3. Associate the image with its long text description, using either:

   • A link immediately following the image to the long text description. For example, <img alt="(short text summary)"> <a href="#desc">Text description of image</a>; or

   • A description of the location of the long text description in the short text summary. For example, <img alt="(short text summary. description follows)"> Long text description.

Source: WCAG 2.0, Technique G73 and WCAG 2.0, Technique G74

2. Images Of Text

Do not use images of text. To customize visual presentation of text, use CSS.

Source: WCAG 2.0, Technique C22

3. Animated Images

Animated images are considered the same as video-only content and the requirements for video-only content apply.

Content Examples

1. Decorative Images

News

Source Code

<h4><img src="img-news-nouvelles.gif" width="40"
height="35" alt="">
News</h4>
<img src="img-lin.gif" width="200" height="12" 
alt="">To follow

Pick A Colour

Source Code

<img src="img-clr.png"
width="16" height="16" alt="">
<a href="#">Pick A Colour</a>

An image with no relationship to other content can be deemed decorative because it serves only an aesthetic purpose, provides no information, and has no functionality.

Source Code

<p><img src="images/img-decor-photo.jpg" width="125" height="120" alt=""
class="float-left">An image with no relationship to other content
can be deemed decorative because it serves only an aesthetic purpose, provides
no information, and has no functionality.</p>

<p><img src="images/img-decor-photo.jpg" width="125" height="120"
alt="Hand writing with pen" class="float-left">The image of the hand writing
with a pen may also be used in a non-decorative context as a simple image.  In this case, it is
being referenced directly and is related to the context of this paragraph.

<p><img src="img-spl.jpg"
alt="The RCMP musical ride
performing" /></p>
<p class="margin-bottom-none">
<strong>Caption:</strong> The
RCMP musical ride performing
at the Sunset Ceremonies in
Ottawa</p

<p><img src="img-spl.jpg"
alt="The RCMP musical ride
performing" /></p>To follow

<p><img
src="img-spl-dog-chien.jpg"
alt="Two puppies" />
</p>

<div class="span-3 margin-bottom-none">
	<p><img src="images/img-pie-en.jpg" width="320" height="251"
alt="Pie chart of favourite movie genres in Mrs. Smyth's Film class.
Data table follows."></p>
</div>
<div class="span-2 margin-bottom-none">
	<table>
		<caption>Figure 5. Favourite movie genres in Mrs. Smyth's
	Film class</caption>
		<tr>
			<th>Genre</th>
			<th>Percentage</th>
		</tr>
		<tr>
			<td>Comedy</td>
			<td>27%</td>
		</tr>
		<tr>
			<td>Action</td>
			<td>18%</td>
		</tr>
		<tr>
			<td>Romance</td>
			<td>14%</td>
		</tr>
		<tr>
			<td>Drama</td>
			<td>14%</td>
		</tr>
		<tr>
			<td>Horror</td>
			<td>11%</td>
		</tr>
		<tr>
			<td>Foreign</td>
			<td>8%</td>
		</tr>
		<tr>
			<td>Science fiction</td>
			<td>8%</td>
		</tr>
	</table>
</div>

<p><img src="images/img-org-en.jpg" id="org" class="margin-top-medium"
alt="Example organizational chart. Description follows."></p><p class="align-center">
<a href="img-org-desc-en.html">Text Description Of Image</a></p>

Web Accessibility Considerations

Cognitive Impairments

• Include supporting images, where possible, in order to accommodate visual comprehension deficits. For example, a Web page that outlines a specific mainframe screen must be textually described for visually impaired users. The addition of screen shot images adds value for users with visual comprehension deficits, like dyslexia. Furthermore, the combination of text and imagery adds value to all users, as some people are textual learners and others are visual learners.

Mobility, Dexterity and Coordination Impairments

• If the image is selectable (for example, a thumbnail), make sure the size of the image is large enough to accommodate users with dexterity issues.

Visual Impairments

• According to the Adaptive Technology Program, alt text used in non-decorative images should help to convey the mood or experience of the site to screen reader users.

Related Links

• Web Content Accessibility Guidelines (WCAG) 2.0 Success Criteria

  • 1.1.1 Non-text Content
  • 1.4.5 Images of Text

• Web Content Accessibility Guidelines (WCAG) 2.0 Sufficient Techniques

  • Decorative Images: H67: Using null alt text and no title attribute on img elements for images that AT should ignore
  • Simple Images: H37: Using alt attributes on img elements
  • Complex Images: G73: Providing a long description in another location with a link to it that is immediately adjacent to the non-text content and G74: Providing a long description in text near the non-text content, with a reference to the location of the long description in the short description
  • Images Of Text: C22: Using CSS to control visual presentation of text