Alt text for images in HTML - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why is alt text important for images?

Which of the following best explains why adding alt text to images is important in web development?

A It adds a border around the image to make it stand out visually.

B It changes the image size automatically based on device screen width.

C It helps search engines understand the image content and improves accessibility for screen readers.

D It allows images to load faster by compressing them.

💡 Hint

Think about users who cannot see images and how they might understand the content.

Alt text provides a description of images for screen readers used by visually impaired users and helps search engines index images properly.

📝 Syntax

intermediate

Identify the correct alt attribute syntax

Which option shows the correct way to add alt text to an image in HTML?

HTML

<img src="flower.jpg" ____ >

A "moolb ni rewolf der A"=tla

B alt='A red flower in bloom'

C alt=A red flower in bloom

D alt="A red flower in bloom"

💡 Hint

Alt text must be inside quotes and properly formatted.

The alt attribute value must be enclosed in quotes (single or double). Option D uses double quotes correctly.

❓ rendering

advanced

What is the visible output when alt text is used?

If an image fails to load in a browser, what will the user see if the image tag has alt text?

HTML

<img src="missing.jpg" alt="A mountain landscape">

A A broken image icon with no text will appear.

B The text 'A mountain landscape' will be shown in place of the image.

C Nothing will appear; the image area will be blank.

D The browser will automatically load a default image.

💡 Hint

Alt text is a fallback description when images cannot load.

When an image cannot load, browsers display the alt text so users understand what was meant to be shown.

❓ selector

advanced

Which CSS selector targets images missing alt text?

You want to style images that do NOT have an alt attribute or have an empty alt attribute. Which CSS selector will select those images?

A img:not([alt]), img[alt=""]

B img[alt="*"]

C img[alt]

D img:empty

💡 Hint

Think about selecting elements missing an attribute or with an empty attribute value.

The selector img:not([alt]) selects images without alt attribute, and img[alt=""] selects images with empty alt text.

❓ accessibility

expert

Best practice for decorative images with alt text

For purely decorative images that add no meaningful content, what is the best practice for the alt attribute to ensure accessibility?

A Use alt="" (empty alt attribute) so screen readers skip the image.

B Use alt="decorative image" to describe the image purpose.

C Omit the alt attribute entirely to hide the image from screen readers.

D Use alt="image" as a generic description.

💡 Hint

Think about how screen readers treat empty alt attributes.

An empty alt attribute tells screen readers to ignore the image, which is best for decorative images that do not add information.

Practice

1. What is the main purpose of the alt attribute in an <img> tag?

easy

A. To add a border around the image

B. To provide a text description of the image for screen readers and when the image cannot load

C. To change the image size on the webpage

D. To link the image to another webpage

Solution

1. Step 1: Understand the role of alt text

   The alt attribute gives a text description of the image content.

2. Step 2: Recognize accessibility and fallback use

   This text helps screen readers for visually impaired users and shows if the image fails to load.

3. Final Answer:

   To provide a text description of the image for screen readers and when the image cannot load -> Option B

4. Quick Check:

   Alt text = image description [OK]

Hint: Alt text describes images for accessibility and fallback [OK]

Common Mistakes:

• Thinking alt changes image size
• Using alt to add styling like borders
• Confusing alt with links

2. Which of the following is the correct way to add alt text to an image in HTML?

easy

A.

B.

C.

D.

Solution

1. Step 1: Identify the correct attribute for alt text

   The correct attribute to describe images is alt.

2. Step 2: Check the syntax of the <img> tag

   <img src="flower.jpg" alt="Beautiful red flower"> uses alt="Beautiful red flower", which is correct HTML syntax.

3. Final Answer:

   <img src="flower.jpg" alt="Beautiful red flower"> -> Option A

4. Quick Check:

   Use alt attribute for image description [OK]

Hint: Use alt="description" inside <img> tag [OK]

Common Mistakes:

• Using non-existent attributes like description or text
• Confusing alt with title attribute
• Omitting quotes around alt text

3. What will a screen reader announce for this image tag?

<img src="logo.png" alt="Company logo">

medium

A. It will say 'Company logo' aloud

B. It will ignore the image and say nothing

C. It will read the file name 'logo.png'

D. It will say 'image' only

Solution

1. Step 1: Understand screen reader behavior with alt text

   Screen readers read the alt attribute to describe images to users.

2. Step 2: Check the alt attribute content

   The alt text is "Company logo", so the screen reader will announce this phrase.

3. Final Answer:

   It will say 'Company logo' aloud -> Option A

4. Quick Check:

   Screen reader reads alt text [OK]

Hint: Screen readers read alt text, not file names [OK]

Common Mistakes:

• Assuming screen readers read image file names
• Thinking screen readers ignore images with alt
• Confusing alt with title attribute

4. Identify the error in this image tag:

<img src="photo.jpg" alt>

medium

A. The alt attribute should be written as alt-text

B. The src attribute is incorrect

C. The img tag is missing a closing tag

D. The alt attribute is missing a value

Solution

1. Step 1: Check the alt attribute syntax

   The alt attribute must have a value, like alt="description". Here it is empty without ="...".

2. Step 2: Confirm other attributes and tag correctness

   The src attribute is correct, and <img> is self-closing in HTML5, so no closing tag needed.

3. Final Answer:

   The alt attribute is missing a value -> Option D

4. Quick Check:

   Alt attribute needs a value in quotes [OK]

Hint: Alt attribute must have a quoted value [OK]

Common Mistakes:

• Leaving alt attribute empty without =""
• Thinking img needs a closing tag
• Using invalid attribute names like alt-text

5. You have a decorative image that adds no meaning to your page. How should you write the img tag for best accessibility?

hard

A.

B.

C.

D.

Solution

1. Step 1: Understand alt text for decorative images

   Decorative images should have empty alt text (alt="") so screen readers skip them.

2. Step 2: Evaluate options for accessibility

   <img src="decorative.png" alt=""> uses empty alt, which is correct. Omitting alt or using generic text causes confusion.

3. Final Answer:

   <img src="decorative.png" alt=""> -> Option C

4. Quick Check:

   Empty alt hides decorative images from screen readers [OK]

Hint: Use alt="" for decorative images [OK]

Common Mistakes:

• Omitting alt attribute entirely
• Using vague alt text like 'image' or 'decorative image'
• Adding unnecessary descriptions for decoration