How to set pictures in css-Front-end Q&A-php.cn

CSS, Cascading Style Sheet, is a style language used for web design, which can make web design more beautiful and readable. Pictures are an integral part of web design, which can help web pages better convey information and attract users' attention. In this article, we will explore how to use CSS to set images to help you achieve better web design.

1. Use attributes to set images

In CSS, the most basic way to set images is to use the background image attribute, that is, background-image. This attribute allows us to use any image as the background of a web page element to achieve various effects. The following is an example of using the background image attribute:

div{
  background-image: url("image.jpg");
}

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In the above example, we use the image "image.jpg" as the background image of the div element. When the page loads, this image will appear in the background of the

element. It should be noted that when using the background-image attribute to set a picture, the path of the picture must be correct.

2. Set the size and position of the image

In addition to setting the image itself, we can also use CSS to control the size and position of the image. Here are some commonly used attributes:

background-size: This attribute is used to set the size of the image. It has a variety of values, including cover, contain and specific pixel size. For example:

div{
  background-image: url("image.jpg");
  background-size: cover;
}

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The above code sets the image "image.jpg" as the background of the div element, while stretching it to cover the entire

element.

background-position: This attribute is used to set the position of the image. For example:

div{
  background-image: url("image.jpg");
  background-position: center;
}

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This code centers the image "image.jpg" in the background of the

element.

3. Use CSS Elf technology

CSS Elf technology is a technology that optimizes web page performance and loading speed. It can merge multiple images into one, thereby reducing the HTTP requests of the web page. . This technology can use the background-position attribute to set the position of the picture and set the corresponding position coordinates for each picture.

For example:

.sprite {
  display: inline-block;
  background-image: url(sprite.png);
}

.icon1 {
  width: 32px;
  height: 32px;
  background-position: 0 0;
}

.icon2 {
  width: 32px;
  height: 32px;
  background-position: -32px 0;
}

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In the above code, we merge two 32×32 pixel images together and then use CSS sprite technology to separate them. In this way, when the web page is loaded, only one image needs to be loaded instead of two images separately, thereby reducing HTTP requests and improving web page performance and loading speed.

Summary

Through the introduction of this article, we have learned about the basic methods of setting images using CSS, how to control the size and position of images, and how to use CSS sprite technology to optimize web page performance. I hope this article can help you better understand how to use CSS to create beautiful web pages.

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