Image source and alt attribute in HTML

Introduction

Images make websites look nice and interesting. The src attribute tells the browser where to find the image. The alt attribute gives a description of the image for people who cannot see it.

When you want to show a picture on a webpage.

When you want to help people who use screen readers understand the image.

When the image cannot load, so the description shows instead.

When you want to improve your website's accessibility and SEO.

When you want to add meaningful descriptions to images for better user experience.

Syntax

HTML

<img src="image-url.jpg" alt="Description of the image">

The src attribute must have the path or URL of the image.

The alt attribute should describe what the image shows in simple words.

Examples

This shows a cat picture with a description for screen readers.

HTML

<img src="cat.jpg" alt="A cute orange cat sitting on a chair">

This loads an image from the internet and describes it as a company logo.

HTML

<img src="https://example.com/logo.png" alt="Company logo">

An empty alt means the image is decorative and screen readers will skip it.

HTML

<img src="flower.png" alt="">

Sample Program

This webpage shows a heading, an image of a cat with a clear description, and a short paragraph below it.

HTML

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Image Example</title>
</head>
<body>
  <h1>My Favorite Animal</h1>
  <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Cat03.jpg/320px-Cat03.jpg" alt="A fluffy gray cat lying on a wooden floor" width="320" height="240">
  <p>This is a picture of a cat.</p>
</body>
</html>

Important Notes

Always include the alt attribute for accessibility.

Use meaningful descriptions in alt to help users who cannot see images.

If the image is purely decorative, use an empty alt="" to avoid confusion.

Summary

The src attribute tells the browser where to find the image.

The alt attribute describes the image for people who cannot see it.

Using both helps make websites better for everyone.

Practice

1. What does the alt attribute in an <img> tag do?

easy

A. Provides a text description of the image for screen readers and when the image can't load

B. Specifies the URL of the image to display

C. Sets the size of the image on the page

D. Adds a border around the image

Solution

1. Step 1: Understand the purpose of the alt attribute

   The alt attribute provides alternative text describing the image content.

2. Step 2: Recognize its use for accessibility and fallback

   This text helps screen readers and shows if the image fails to load.

3. Final Answer:

   Provides a text description of the image for screen readers and when the image can't load -> Option A

4. Quick Check:

   alt describes image content [OK]

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

Common Mistakes:

• Confusing alt with src attribute
• Thinking alt controls image size
• Using alt to add styling

2. Which of the following is the correct syntax to add an image with source "photo.jpg" and alt text "A sunset"?

easy

A.

B.

C.

D.

Solution

1. Step 1: Identify correct tag and attributes

   The correct tag is <img> with attributes src and alt.

2. Step 2: Check attribute names and order

   <img src="photo.jpg" alt="A sunset"> uses correct attribute names and syntax: src="photo.jpg" and alt="A sunset".

3. Final Answer:

   <img src="photo.jpg" alt="A sunset"> -> Option A

4. Quick Check:

   Correct tag and attributes = <img src="photo.jpg" alt="A sunset"> [OK]

Hint: Use <img> with src and alt attributes exactly named [OK]

Common Mistakes:

• Using <image> instead of <img>
• Using 'source' instead of 'src'
• Using 'description' instead of 'alt'

3. What will the browser display if this code is used and the image file "logo.png" is missing?

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

medium

A. Nothing will show, just empty space

B. The browser will crash

C. An error message will pop up

D. The text "Company Logo" will appear instead of the image

Solution

1. Step 1: Understand what happens when image source is missing

   If the image file can't be found, the browser shows the alt text as a fallback.

2. Step 2: Identify the alt text in the code

   The alt text is "Company Logo", so this text will display in place of the missing image.

3. Final Answer:

   The text "Company Logo" will appear instead of the image -> Option D

4. Quick Check:

   Missing image shows alt text [OK]

Hint: Missing images show alt text in browser [OK]

Common Mistakes:

• Expecting no output or blank space
• Thinking browser shows error popups
• Assuming browser crashes

4. Find the error in this image tag:

<img src="picture.jpg" alt>

medium

A. The img tag should be closed with

B. The src attribute is misspelled

C. The alt attribute is missing a value

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

Solution

1. Step 1: Check the alt attribute syntax

   The alt attribute is present but has no value assigned, which is invalid.

2. Step 2: Confirm correct attribute names and tag usage

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

3. Final Answer:

   The alt attribute is missing a value -> Option C

4. Quick Check:

   Alt attribute must have a value [OK]

Hint: Alt attribute always needs a descriptive value [OK]

Common Mistakes:

• Leaving alt attribute empty
• Adding closing tag
• Changing alt attribute name incorrectly

5. You want to add an image that shows a cat playing with a ball. Which is the best way to write the <img> tag for accessibility and SEO?

hard

A.

B.

C.

D.

Solution

1. Step 1: Understand the purpose of alt text for accessibility and SEO

   Alt text should clearly describe the image content to help screen readers and improve search engine understanding.

2. Step 2: Evaluate the options for descriptive quality

   <img src="cat-ball.jpg" alt="Cat playing with a ball"> describes the image specifically as "Cat playing with a ball", which is clear and meaningful.

3. Final Answer:

   <img src="cat-ball.jpg" alt="Cat playing with a ball"> -> Option B

4. Quick Check:

   Descriptive alt text improves accessibility and SEO [OK]

Hint: Use clear, specific alt text describing the image content [OK]

Common Mistakes:

• Using vague alt text like 'image' or 'cute'
• Omitting alt attribute entirely
• Using unrelated or too short alt text