How to add pictures to html

HTML is a markup language used to create text, images, videos and other content in web pages. Pictures are one of the essential elements in web page production. How to correctly add pictures is a skill that every web page producer needs to master.

1. Basic syntax

In HTML, use the img tag to insert pictures. The full name of img is "image", which means picture. The following is the basic syntax of the img tag:

<img src="图片文件路径" alt="图片描述">

The img tag has two main attributes: src and alt. src refers to the path of the image file, and alt refers to the text description that will be displayed when the page cannot display the image normally.

Among them, the src attribute must be filled in, while the alt attribute is optional. If the image path is incorrect, the image will not be displayed. If the alt attribute is not set, a string of meaningless text may be displayed on the page where the image cannot be displayed normally.

The image path can be a local path or a network path. The local path refers to the path of the image file stored on the local computer; the network path refers to the path of the image file accessed through the network, such as images downloaded from the Internet.

2. The path of local pictures

The paths of local pictures are divided into absolute paths and relative paths. The absolute path specifies the location of the image in the entire file system, and you need to write the complete path; the relative path is the path description starting from the HTML file, and you only need to write the location of the image relative to the HTML file.

The following are two ways of writing local image paths.

1. Absolute path

The absolute path refers to the location of the image in the entire file system. Depending on the operating system, the absolute path will be slightly different. In Windows systems, absolute paths start from the drive letter, for example:

C:\Users\Administrator\Pictures\test.jpg

In Mac OS X systems, absolute paths start from the root directory, for example:

/Users/username/Documents/test.jpg

The disadvantages of this approach are , each web page must use the complete file path. If the file storage location changes, the code needs to be modified.

2. Relative path

The relative path refers to the location of the image relative to the HTML file. The simpler the directory structure, the easier it is to use relative paths. In HTML files, "." represents the directory where the current file is located, and ".." represents the directory above the directory where the current file is located. If the image and the HTML file are in the same directory, relative paths can be used, for example:

<img src="./images/test.jpg" alt="测试图片">

If the image is stored in the images folder in the directory where the HTML file is located, the path is "./images/test.jpg".

3. Internet pictures

Internet pictures refer to pictures obtained from the Internet. In HTML, you can use the img tag to insert network images just like local images.

Network images are usually represented by URL (Uniform Resource Locator), which is a string composed of protocol name, host name, file path and file name. For example, the URL to access Baidu pictures is:

https://www.baidu.com/img/bd_logo1.png

Among them, "https://" is the protocol name, indicating that the HTTPS protocol is used for data transmission; "www.baidu.com" is the host name; "img/ bd_logo1.png" is the file path and file name.

When adding network pictures, just copy the URL of the network picture to the src attribute of the img tag, for example:

<img src="https://www.baidu.com/img/bd_logo1.png" alt="百度logo">

Network pictures are more convenient, don’t worry about the path problem, as long as the picture If the URL is no problem, you can use the img tag to insert the image directly into the HTML.

4. Image Adaptation

In the process of web page production, a common need is to make the image size adaptive, so that it can have better display effects on different devices and screens. . Commonly used methods include using CSS to set properties such as width, height, and max-width.

1. Use CSS to set the width and height

The width and height attributes in CSS can set the width and height of the image respectively, for example:

<style>
    img {
        width: 100%;
        height: auto;
    }
</style>

where , setting width to 100% means that the width of the picture will change as the available space changes; setting height to auto means that the height will be automatically adjusted according to the proportion of the width, maintaining the original proportion.

2. Use CSS to set max-width

Using the max-width attribute can make the image automatically shrink proportionally when it exceeds a certain width, but it will not be smaller than its original size. For example:

<style>
    img {
        max-width: 100%;
        height: auto;
    }
</style>

Among them, max-width is set to 100%, which means that the maximum width of the picture will not exceed its available space and will not exceed the original size. Height is set to auto, which means that the height will be automatically adjusted according to the ratio of the width. , keeping the original proportions.

In short, when adding images to web pages, you must consider issues such as image path, image description, image size and adjustment. As long as you master the basic syntax and common methods, you can flexibly use the img tag in HTML to make the web page more colorful.

The above is the detailed content of How to add pictures to html. For more information, please follow other related articles on the PHP Chinese website!