Depending on how heavily your site’s look, feel, and branding rely on the background images, choosing the right size could have a huge impact overall. The output of above Html code is shown in the following screenshot: Using Internal CSS. And please feel free to give comments on this tutorial. In this step we create a simple markup and use css background property to add image to body background.You may also like animated background using CSS3. I found the above solutions didn't work for me (on current versions of firefox and safari at least). Note: to change the original size, you have to specify the width and height with CSS as you can see in the demo below. For instance, in the demo above, I didn't modify the size of the SVG image, so it assumed its original size (which was a width of 600.53015px and a height of 915.11162px). Increase the Size without "Stretching" the Image out of Proportion. It's also at the bottom-most position in our "div stack" (z-index 1) We set the image url via a CSS custom property, that's set via the style attribute in our HTML */.image-box__background {background: var (--image-url) center center no-repeat; background-size: cover; z-index: 1} /* The overlay div is just a colored element with some opacity. The steps below guide users wanting to keep an image at its original file size (in KB or MB) and resize the display size of the image with HTML.Although this is possible, we still suggest you resize an image using an image editor to reduce the file size and reduce the download time of the image.. What program can I use to view, edit, or create images? Now you can use media queries to swap out that image instead of relying on JavaScript. Example below. Test it Now. In my case I'm actually trying to do it with an img tag, not background-image, though it should also work for background-image if you use z-height: This property offers two special values: contain and cover. To use an image as a CSS background, use the background-size property. The background-size property also accepts values that prevent the image from stretching out of proportion.. body { background-image: url(img.jpg); background-position: center top; background-size: 100% auto; } This will set your background image to 100% width and allow the height to overflow. If we want to change the size of an image or picture using an internal cascading stylesheet which is to be displayed on a web page, we have to follow the steps which are given below. Using these steps, we can easily change the size of any image. The background-size: attribute allows you to control the way your background image fills a space. Let's see examples with these values. Resize images with the CSS max-width property¶ There is a better way for resizing images responsively. Example of resizing an image using the background-size property set to “contain”:¶ The background image size question is important because it is a balancing act of trade-offs to get the best performing and best looking site. background-size: contain; ‘Contain’ tells the client to keep the background image to its original size and to fill the element it is within. "Repeating" Background Images. In other words, instead of just appearing once, the background image will appear again and again until it uses up the full size of its parent container. If the background image is smaller than the HTML element that it's applied to, it will "repeat" across the full width and height of the HTML element. 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. Thats all, this is how to add full page background image using HTML and CSS.You can customize this code further as per your requirement. Using background-size: cover. Using the dimensions from the example above, the element it will fill is a 640px x 400px table. The trick is to use height: auto; to override any already present height attribute on the image.