4 Ways to Keep Image Aspect Ratio In HTML CSS

Welcome to a tutorial on how to keep the aspect ratio of an image in HTML and CSS. So you have placed an image on your webpage and decided to resize it a little… But the image went out of out-of-proportions and it now looks funky. Just how do we keep the aspect ratio? Let us walk through some examples in this guide – Read on!

 

 

TABLE OF CONTENTS

 

 

EXAMPLE CODE DOWNLOAD

Click here to download. I have released it under the MIT license, so feel free to build on top of it or use it in your own project.

 

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TUTORIAL VIDEO

 

METHOD 1) AUTOMATIC WIDTH/HEIGHT

<style>
#demoA { width: 300px; height: auto; }
#demoB { width: auto; height: 300px; }
</style>
 
<img src="doge.png" id="demoA">
<img src="cate.png" id="demoB">

This is the easiest way to maintain the aspect ratio, and it should be self-explanatory:

• Manually define the width, then set the height to auto.
• Vice versa, define the height and set the width to auto.

 

 

METHOD 2) 100% WIDTH

<style>
#demoC, #demoD { width: 100%; }
/* optional */
#demoC { max-width: 550px; }
#demoD { max-width: 350px; }
</style>
 
<img src="doge.png" id="demoC">
<img src="cate.png" id="demoD">

How does one create a responsive image that scales itself to fit, while maintaining aspect ratio?

• Just set 100% width on the image.
• Optional – Limit the max width, so that it does not stretch too much.

 

METHOD 3) OBJECT-FIT

<style>
 /* (A) FIXED IMAGE DIMENSIONS */
img.demoE {
  width: 500px;
  height: 200px;
}
 
/* (B) RESIZE BEHAVIOR */
img.contain { object-fit: contain; }
img.cover { object-fit: cover; }
img.scale { object-fit: scale-down; }
img.fill { object-fit: fill; }
</style>
 
<div>Contain:</div>
<img src="cate.png" class="demoE contain">
 
<div>Cover:</div>
<img src="cate.png" class="demoE cover">
 
<div>Scale Down:</div>
<img src="cate.png" class="demoE scale">
 
<div>Fill:</div>
<img src="cate.png" class="demoE fill">

What if we want an image to be contained within fixed dimensions, but scaled proportionally to the aspect ratio? Introducing object-fit.

• none – The default if not defined, the image will not be resized.
• contain – The image will be resized to fit into the box while maintaining the aspect ratio.
• cover The image will be resized to cover the entire box while maintaining the aspect ratio.
• scale-down – The image will be resized using none or contain, whichever gives a smaller image.
• fill – You will probably not want to use this one, it stretches the image to fit the box, disregarding the aspect ratio.

 

 

METHOD 4) PADDING TRICK

<style>
#demoF {
  width: 100%;
  padding-bottom: 56.25%; /* 16:9 ratio = 9 / 16 = 0.5625 */
  background: no-repeat center/cover url("cate.png");
}
</style>

<div>This will maintain 16:9 ratio:</div>
<div id="demoF"></div>

Just what kind of sorcery is this? This final method is an old trick that uses padding to maintain the aspect ratio.

• First, create a <div> container with width: 100%. As above, this will scale to fit.
• The padding-bottom is calculated relative to the width of the box, so:
  • padding-bottom: 100% will create a square.
  • padding-bottom: 50% will have a height that is half of the current width.
  • padding-bottom: 25% will have a height that is a quarter of the current width.
  • To maintain a ratio of 16:9, we set 16 / 9 = 56.25%.
• Lastly, set the image as the background, centered in the container.

 

 

INFOGRAPHIC CHEATSHEET

 

 

LINKS & REFERENCES

• CSS Object Fit – MDN
• Aspect Ratio Boxes – CSS Tricks
• Rounded Images In HTML CSS – Code Boxx
• Clip & Crop Images In HTML CSS – Code Boxx
• Auto-Resize Images In HTML CSS – Code Boxx