The alt attribute provides a textual alternative to an image. It is used whenever the actual image cannot be rendered. Common reasons for that include:

• The image can no longer be found
• Slow internet connections, while waiting for the image to download
• Visually impaired users using a screen reader software
• Images loading is disabled, e.g. to reduce data consumption on mobile phones

Noncompliant Code Example

<img src="foo.png" />                                           <!-- Non-Compliant -->
<img src="foo.png" alt="" />                                    <!-- Non-Compliant -->
<input type="image" src="bar.png" />                            <!-- Non-Compliant -->

Compliant Solution

<img src="foo.png" alt="Some textual description of foo.png" />
<input type="image" src="bar.png" alt="Textual description of bar.png" />