Image sizing basics in HTML - Cheat Sheet & Quick Revision

Recall & Review

beginner

What attribute controls the width of an image in HTML?

The width attribute controls the width of an image in HTML. You can set it in pixels or as a percentage.

beginner

How do you keep an image's aspect ratio when resizing it?

To keep the aspect ratio, set only width or height, not both. The browser adjusts the other dimension automatically.

beginner

What CSS property can you use to control image size?

You can use the CSS properties width and height to control image size. For example, img { width: 50%; height: auto; }.

beginner

What happens if you set both width and height attributes to different proportions than the original image?

The image will stretch or squash, changing its original shape and possibly looking distorted.

intermediate

Why is it better to use CSS for image sizing instead of HTML attributes?

Using CSS separates content from design, making it easier to update styles and keep HTML clean. CSS also offers more control and responsiveness.

Which attribute sets the width of an image in HTML?

A width

B size

C length

D scale

The width attribute sets the width of an image in HTML.

If you want to keep an image's shape, what should you do when resizing?

A Set both width and height to new values

B Set only width or only height

C Set width and height to zero

D Use the <code>size</code> attribute

Setting only width or only height lets the browser keep the aspect ratio automatically.

Which CSS property is used to control image height?

A margin

B font-size

C height

D padding

The CSS property height controls the height of an image.

What is the visual effect of setting width and height to values that don't match the image's original ratio?

A Image stretches or squashes

B Image becomes blurry

C Image disappears

D Image stays the same

The image will stretch or squash, changing its shape and possibly looking distorted.

Why is CSS preferred over HTML attributes for image sizing?

A CSS is faster to write

B HTML attributes don't work in modern browsers

C CSS makes images load faster

D CSS allows better control and responsiveness

CSS offers more control, keeps design separate from content, and supports responsive layouts.

Explain how to resize an image in HTML while keeping its original shape.

Think about which attribute to set to avoid distortion.

Describe the difference between resizing images using HTML attributes and CSS.

Consider how design and content are managed.

Practice

1. Which HTML attribute is used to set the width of an image directly in the tag?

easy

A. width

B. size

C. length

D. scale

Solution

1. Step 1: Identify image sizing attributes

   The width attribute is used in the <img> tag to set the image width in pixels or percentage.

2. Step 2: Confirm correct attribute name

   Among the options, only width is a valid HTML attribute for image sizing.

3. Final Answer:

   width -> Option A

4. Quick Check:

   Image width attribute = width [OK]

Hint: Use width or height attributes for quick sizing [OK]

Common Mistakes:

• Confusing size with width
• Using CSS property names as HTML attributes
• Trying to use scale which is not valid

2. Which of the following is the correct way to set an image width to 200 pixels in HTML?

easy

A. <img src='photo.jpg' width='200px'>

B. <img src='photo.jpg' style='width: 200'>

C. <img src='photo.jpg' width='200'>

D. <img src='photo.jpg' height='200px'>

Solution

1. Step 1: Understand HTML attribute value format

   In HTML, the width attribute expects a number representing pixels without units.

2. Step 2: Check each option

   <img src='photo.jpg' width='200px'> uses '200px' which is invalid for the width attribute. <img src='photo.jpg' width='200'> correctly uses '200' without units. <img src='photo.jpg' style='width: 200'> uses CSS syntax incorrectly inside an attribute. <img src='photo.jpg' height='200px'> sets height, not width.

3. Final Answer:

   <img src='photo.jpg' width='200'> -> Option C

4. Quick Check:

   Width attribute value is number only [OK]

Hint: Use numbers only for width/height attributes, no units [OK]

Common Mistakes:

• Adding 'px' units inside width or height attributes
• Confusing CSS style syntax with HTML attributes
• Setting height instead of width by mistake

3. What will be the visual result of this HTML code?

<img src='flower.jpg' width='150' height='100'>

medium

A. Image not shown due to invalid attributes

B. Image shown with width 150px and height 100px, possibly distorted

C. Image shown with height 100px, width auto to keep ratio

D. Image shown with width 150px, height auto to keep ratio

Solution

1. Step 1: Understand width and height attributes together

   When both width and height are set, the image is forced to those exact dimensions, ignoring original proportions.

2. Step 2: Predict visual effect

   Because the original image ratio may differ, forcing both width and height can distort the image shape.

3. Final Answer:

   Image shown with width 150px and height 100px, possibly distorted -> Option B

4. Quick Check:

   Both width and height set = fixed size, possible distortion [OK]

Hint: Setting both width and height fixes size, may distort image [OK]

Common Mistakes:

• Assuming height auto adjusts when both attributes set
• Thinking image keeps original ratio automatically
• Believing invalid attributes cause image not to show

4. Identify the error in this HTML code for sizing an image:

<img src='cat.png' width='300' height='auto'>

medium

A. Using 'auto' in height attribute is invalid in HTML

B. Using '300' without units in width attribute is invalid

C. Missing closing slash in <img> tag

D. No error, code is correct

Solution

1. Step 1: Check width attribute value

   The width attribute correctly uses the number '300' without units.

2. Step 2: Check height attribute value

   Height attribute does not accept 'auto' as a value in HTML attributes; it only accepts numbers.

3. Final Answer:

   Using 'auto' in height attribute is invalid in HTML -> Option A

4. Quick Check:

   Height attribute must be number, not 'auto' [OK]

Hint: Height and width attributes accept only numbers, no 'auto' [OK]

Common Mistakes:

• Using CSS values like 'auto' in HTML attributes
• Thinking <img> needs closing slash in HTML5
• Thinking width attribute requires 'px' units

5. You want an image to always fill the width of its container but keep its height proportional. Which CSS style should you use?

hard

A. width: auto; height: auto;

B. width: auto; height: 100%;

C. width: 100px; height: 100px;

D. width: 100%; height: auto;

Solution

1. Step 1: Understand responsive image sizing

   Setting width: 100% makes the image fill the container's width.

2. Step 2: Maintain aspect ratio

   Setting height: auto lets the browser calculate height to keep the image's original proportions.

3. Final Answer:

   width: 100%; height: auto; -> Option D

4. Quick Check:

   Width 100% + height auto = responsive proportional image [OK]

Hint: Use width 100% and height auto for proportional responsive images [OK]

Common Mistakes:

• Setting fixed height breaks aspect ratio
• Using auto width with fixed height distorts image
• Setting both width and height fixed loses responsiveness