How to Make HTML Background Image Full Screen?

Pre-requisites

1. HTML for the structure of our image.
2. CSS for styling and making our background image responsive.

What are we Creating?

Here we'll learn how to stretch a background image to cover the entire browser viewport. The CSS background-size property will be used to accomplish this, and JavaScript is not required. Background images are often stretched out to cover the entire browser viewport by web designers as it looks enticing to the users who are visiting our websites. It is pretty easy to accomplish this task by using a few lines of CSS in our projects. The final output of what we would create is shown below :

How to Make Full-Screen Responsive Background Image with CSS

To make our images responsive, we plan to do the following:

1. Fill the Entire Viewport with the background-size Property

It is possible to set the CSS background-size property to cover. Using this value, the browser will automatically and proportionally scale the background image's width and height so that they are either equal to or greater than the view port's width and height.

2. Use Media Queries to Provide a Smaller Background Image for Mobile Devices

A scaled-down version of the background image file will be served to speed up the page load on small screens with a media query. Choosing this option is optional.

What are the benefits of serving a smaller background image on a mobile device? In the demo, I used an image of about $5976*3570$px.

With this size, we'll be covered on the vast majority of widescreen computer monitors currently available. However, it will require us to serve up a $1.5MB$ file.

It is never a good idea for a background photo to take up such a large amount of data, but it is especially bad for mobile Internet. Further, the image dimension is too large on small-screen devices.

We can make the images responsive by using the following approach:

Here is all the markup you need:

We will assign the image to be used as a background to the body element so that the image always covers the entire viewport of our browsers.

Now our background image covers the entire viewport of the browser, and we're going to assign the image to the body element. Nevertheless, this technique works on any element at the block level (such as a div or a form).

The background image will always scale so that it covers the whole block-level container if the container's width and height are fluid.

Here's where the magic happens. Whenever this property/value pair is set, the browser scales the background image to conform to an element's width and height. Here we're using the body element as an example.

When a browser sees a background image that is smaller than the body element's dimensions, it will programmatically enlarge the image. This happens on high-resolution screens with small background images.

It is well known that when images are scaled above their natural dimensions, the image quality degrades (pixelation occurs).

Image quality is negatively affected when images are scaled beyond their natural dimensions.

Consider that when selecting the image for your project, As the demo uses $5976*3570$px photos for larger screens, it'll be a while before there are problems.

Depending on the size of your background image, the browser can display it as tiles.

Using no-repeat will prevent this from happening:

We will keep our image centered on keeping things looking nice:

In this way, the image will be vertically and horizontally centered at all times.

The next problem is when the height of the content is greater than the height of the visible viewport. In this case, there will be a scroll bar. The background image must remain in place during scrolling down. Otherwise, either the image runs out at the bottom of the background or moves when the user scrolls down (which can be very distracting).

This can be accomplished by setting the background-attachment property to fixed.

Using short notation, all of the background properties described above can be included :

As an example :

Now we have achieved a fully responsive image that will always cover the entire background and look enticing to the users who visit our website. The code to achieve it is shown below :

Output:

The output with the usage of the media query is shown below :

If your mobile connection is slow, you can downsize your original image using Photoshop or another image-editing software.

One of the major disadvantages of using the media query is that, when the browser window is resized, for example, from $1200px$ to $640px$ (or vice versa), the background image will momentarily flicker while it loads.

HTML Background Image Full Screen Without CSS

A variety of methods can be used to set the HTML background image to full screen. In this example, the image will cover the entire screen. This can be done with or without CSS. As you can see in the example below, when we zoom in and out, there is no change in the background image, which is all done using the HTML attributes without adding any CSS.

1. The first property used here is a background image, which sets an image as the background by using the URL.
2. Background-repeat is the next attribute used to keep our image from repeating.
3. Background size is one of the most important attributes used here because it fixes the image in the background so that it does not change when the webpage is zoomed in and out. The cover is given as the value.

Output: