Web Accessibility: Alt Text Best Practices

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Questions and Answers

What is the primary function of alternative text in web images?

To provide context and meaning of the image within its surrounding content (correct)

To describe the technical specifications of the image

To serve as a title for the image

To enhance the aesthetic appeal of the web page

Which of the following is NOT a suitable alt text for an image of Ellen Ochoa?

Ellen Ochoa

Astronaut Ellen Ochoa

Image of Ellen Ochoa, Astronaut (correct)

Ellen Ochoa, the first Hispanic woman to go into space

Why is an empty alt attribute not considered appropriate for an informative image?

It confuses the screen reader software

It provides too much information

It violates web design standards

It does not convey any useful content (correct)

What aspect of the image is important to consider when determining its alt text?

The image's function and surrounding text Signup and view all the answers

When is it acceptable to use alt="" for an image?

When the image is purely decorative Signup and view all the answers

What would be the best alt text for an image that is the only content within a link related to Ellen Ochoa?

Astronaut Ellen Ochoa Signup and view all the answers

Which of the following statements about alternative text is true?

It should avoid redundancy while accurately reflecting the image content Signup and view all the answers

What does a screen reader typically announce for an image with appropriate alt text?

Link, Image, Ellen Ochoa Signup and view all the answers

What is typically sufficient alternative text for a company logo image?

Acme Company Signup and view all the answers

Why is the longdesc attribute generally not recommended?

It lacks good support in screen readers. Signup and view all the answers

Which description is the most informative for the image of George Washington?

Painting of George Washington crossing the Delaware River Signup and view all the answers

What is essential for creating alternative text for a complex image?

It must be provided in a separate location if too lengthy. Signup and view all the answers

What is a key aspect to consider when selecting alternative text for images?

The context and relevance of the image content. Signup and view all the answers

What should not be included in alternative text for a logo linked to the home page?

The word 'logo' Signup and view all the answers

Which of the following is not a reason why alternative text is important?

It creates better aesthetics on the site. Signup and view all the answers

Which of the following is an incorrect method of implementing alternative text?

Using generic terms for specific images. Signup and view all the answers

How should alternative text be formulated for iconic images?

By giving a brief but specific content description. Signup and view all the answers

In the context of web accessibility, which group benefits significantly from alternative text?

All users, including those with varying needs. Signup and view all the answers

What is the primary reason for including redundancy in the alt text of linked images?

To ensure screen reader users understand the link's function Signup and view all the answers

When is it appropriate to use empty alt text for an image?

When the image serves a decorative purpose only Signup and view all the answers

What should the alt text communicate for an image button that initiates a search?

Search Signup and view all the answers

What would be the most appropriate alt text for a linked PDF icon?

Download PDF Signup and view all the answers

What can be inferred about server-side image maps in relation to accessibility?

They are only usable with mouse interactions Signup and view all the answers

In what case is it unnecessary to include the function of an image in the alt attribute?

When the surrounding text conveys the function clearly Signup and view all the answers

What should be done if an image that is only decorative is included in the webpage?

Convert the image to a background image using CSS Signup and view all the answers

What is the main issue with using descriptions like 'PDF icon' for alt text of an image in certain contexts?

The term 'icon' is redundant in those contexts Signup and view all the answers

How should alt text be structured for a map image with functional hot spots?

Main image conveys content, alt text describes each hot spot Signup and view all the answers

Why is verbose alt text often not ideal for accessibility?

It can confuse screen reader users Signup and view all the answers

What is an appropriate alt text for an image that visually represents a handshake in a business context?

Handshake Signup and view all the answers

What is the recommended approach for image buttons displaying rasterized text?

Replace with actual text styled with CSS Signup and view all the answers

What does it mean for an image to be labeled as 'decorative'?

It serves only a visual enhancive purpose Signup and view all the answers

What issue arises from providing alt text that repeats information conveyed in adjacent text?

It may confuse users navigating with screen readers Signup and view all the answers

Study Notes

Alternative Text Best Practices

Alternative text (alt text) serves vital functions for images on web pages, especially for users with visual impairments using screen readers.
Images' meaning can't be fully understood by algorithms alone. Alt text clarifies image content and function within the context of the surrounding text.
Alt text can be used in two ways:
- A useful function for images is necessary for linking them or within or to elements.
- If image conveys content fully represented in adjacent text alt="" is sufficient.

Assessing Image Content and Function

Image function: Only linked images, image maps, or images within have function.
Image content assessment: Harder for complex images.
- If image's content aligns with accompanying text, alt="" might be sufficient.
If image content lacks meaning without the surrounding text, provide more detailed alt text to guide screen readers.

Alt Text for Different Image Types

Linked Images: Alt text needs to describe the image's function and content if no adjacent text explains its purpose.
- Redundancy is acceptable if conveying the content is crucial for screen readers.
Images within links: Alt text only needs to describe the function of the linked item, as adjacent text usually explains the details.
Icons: Alt text must correctly represent the icon's function or linked content.
- Avoid redundancy ("PDF icon" is less useful than "PDF" or "Download PDF file", etc. when describing content).
Decorative images: Use no alt text (alt="") when decorative; if an image is not essential, remove it from the page.
Images with complex content (charts, graphs, maps): If alt text is insufficient, use a separate descriptive element in a or data table linked to the image.
Images presenting a part of a larger document: If the image shows part of a larger document, describing the content of the image as a whole or the part it depicts is vital.
Logos: For branding logos, "company name" as alt text will usually suffice, especially when linking to the home page.
Non-linked images (e.g., paintings): Provide alt text that accurately describes the image and depicts the content, but don't make it too verbose. Use descriptive language, including context if appropriate. "Painting of George Washington crossing the Delaware River" is more descriptive than just "Painting of George Washington."
Image buttons: Alt text for image buttons should describe their function when activated (e.g., "Search," "Submit").
Image maps: Alt text for image maps should focus on the content of the main image that is not conveyed by the hotspots. Each hotspot must also have its own alt text describing its individual function or content.
CSS images: Replace decorative images with CSS background images. Provide alternative text to address relevant page content if needed.

Avoiding Redundancy and Redundant Information

Avoid alt text that is redundant (not unique information) and verbose—the alt attribute should communicate the content concisely and accurately.
Assess image content to prevent redundancies with text adjacent to it and avoid extraneous information that is not visually conveyed within the image.
User-testing helps determine if the alt text is appropriate and accurate.

Deprecated Attributes

Avoid using the longdesc attribute, as screen readers do not support it reliably.

Other important consideration

Client-side vs. server-side image maps: Client-side image maps are better for accessibility because they are perceivable by screen readers.
Replacing rasterized text with true text can also improve accessibility. Screen reader users will receive the same visual information without relying on images.

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Description

This quiz covers essential best practices for writing effective alternative text (alt text) for images on web pages. It focuses on the importance of alt text for users with visual impairments and how it enhances image understanding and web accessibility. Test your knowledge on assessing image content and function, as well as alt text application based on different image types.