Responsive Web Design - Images
Resize the browser window to see how the image scales to fit the page.
Using The width Property
If the width property is set to a percentage
and the height property is set to "auto", the image will be
responsive and scale up and down:
Notice that in the example above, the image can be scaled up to be larger
than its original size. A better solution, in many cases, will be to use the
max-width property instead.
Using The max-width Property
If the max-width property is set to 100%, the image will scale down if it has to, but never scale up to be larger than its
original size:
Add an Image to The Example Web Page
Background Images
Background images can also respond to resizing and scaling.
Here we will show three different methods:
1. If the background-size property is set to "contain", the
background
image will scale, and try to fit the content area. However, the image will keep its aspect ratio (the proportional relationship
between the image's width and height):
Here is the CSS code:
Example
div {
width: 100%;
height: 400px;
background-image: url('img_flowers.jpg');
background-repeat: no-repeat;
background-size: contain;
border: 1px solid red;
}
Try it Yourself »
2. If the background-size property is set to "100% 100%", the background image will stretch to cover the entire content area:
Here is the CSS code:
Example
div {
width: 100%;
height: 400px;
background-image: url('img_flowers.jpg');
background-size: 100% 100%;
border: 1px solid red;
}
Try it Yourself »
3. If the background-size property is set to "cover", the background image will scale
to cover the entire content area. Notice that the "cover" value keeps the aspect
ratio, and some part of the background image may be
clipped:
Here is the CSS code:
Example
div {
width: 100%;
height: 400px;
background-image: url('img_flowers.jpg');
background-size: cover;
border: 1px solid red;
}
Try it Yourself »
Different Images for Different Devices
A large image can be perfect on a big computer screen, but useless on a small device. Why load a large image when you have to scale it down anyway? To reduce the load, or for any other reasons, you can use media queries to display different images on different devices.
Here is one large image and one smaller image that will be displayed on different devices:
Example
/* For width smaller than 400px: */
body {
background-image:
url('img_smallflower.jpg');
}
/*
For width 400px and larger: */
@media only screen and (min-width: 400px)
{
body {
background-image: url('img_flowers.jpg');
}
}
Try it Yourself »
You can use the media query min-device-width, instead of min-width, which
checks the device width, instead of the browser width. Then the image will not change when you resize the browser window:
Example
/* For devices smaller than 400px: */
body {
background-image:
url('img_smallflower.jpg');
}
/*
For devices 400px and larger: */
@media only screen and (min-device-width: 400px)
{
body {
background-image: url('img_flowers.jpg');
}
}
Try it Yourself »
The HTML <picture> Element
The HTML <picture> element gives web
developers more flexibility in specifying image resources.
The most common use of the <picture>
element will be for images used in responsive designs. Instead of having one
image that is scaled up or down based on the viewport width, multiple images can
be designed to more nicely fill the browser viewport.
The <picture> element works similar to the <video> and
<audio> elements. You set up different sources, and the first source that fits the
preferences is the one being used:
Example
<picture>
<source srcset="img_smallflower.jpg" media="(max-width:
400px)">
<source srcset="img_flowers.jpg">
<img
src="img_flowers.jpg" alt="Flowers">
</picture>
Try it Yourself »
The srcset attribute is required, and defines the source of the image.
The media attribute is optional, and accepts the media queries you find in
CSS @media rule.
You should also define an <img> element for browsers that do not support the
<picture> element.
