The core of optimizing images for web pages is to balance quality and loading speed. The key steps include: 1. Select a suitable format such as JPEG, PNG, WebP and SVG; 2. Control the size and resolution and crop according to the display area; 3. Use lossy or lossless compression to reduce volume; 4. Apply lazy loading and responsive image technology to improve loading efficiency.
Optimizing images for web pages is the key to balancing quality and loading speed. Too large images will slow down the page, affecting user experience and SEO ranking; excessive compression will affect the display effect. The key is to choose the right format, control the size, and appropriate compression.
1. Select the appropriate picture format
Different scenarios are suitable for different image formats, and the common ones are JPEG, PNG, WebP and SVG:
- JPEG : Suitable for photos or rich colors, supports lossy compression and smaller files.
- PNG : Suitable for graphics that require a transparent background or clear lines (such as LOGO), but files are usually larger than JPEG.
- WebP : The format launched by Google can maintain high quality while achieving smaller size, and its compatibility is getting better and better.
- SVG : Vector format, suitable for icons and simple graphics, magnification without distortion, and the file is also very small.
If you are not sure which one to use, you can try WebP first, which is supported by most modern browsers.
2. Control image size and resolution
Many websites load slowly because they directly use the camera to take original pictures - a few MB. In fact, it is rare to require pictures that exceed 2,000 pixels wide on a web page.
- Adjust size : Crop the picture according to the actual size of the display area. For example, if a carousel picture is only displayed as 800px wide, there is no need to upload 4000px.
- Unified proportions : Avoid automatic stretching of the browser and cut into appropriate proportions according to the page layout in advance (such as 16:9 or 4:3).
- Resolution recommendation : Generally, 72dpi is enough for web pictures, and there is no need to 300dpi like printing.
You can use Photoshop, GIMP, or online tools such as Squoosh or TinyPNG to resize in batches.
3. Compress pictures and reduce file volume
There are two types of compression: lossy compression and lossless compression .
- Lossy compression : It will sacrifice some visual details for smaller size, suitable for photo-like pictures.
- Lossless compression : retains all original information and is suitable for details such as icons, screenshots, etc.
Several practical tools are recommended:
After compression, it can usually reduce the volume by 50% to 80%, and the difference cannot be seen by the naked eye.
4. Use lazy loading and responsive images
Lazy Load means that the image starts loading only when the user scrolls near it, which can significantly increase the loading speed of the first screen.
-
HTML5 supports
loading="lazy"attribute, just add it to the img tag:<img src="/static/imghw/default1.png" data-src="example.jpg" class="lazy" alt="example diagram" loading="lazy">
For responsive websites, you can also use the
<picture></picture>tag orsrcsetattribute to allow the browser to automatically select pictures of the appropriate size according to the device size.
These methods can be used in combination to allow users on different devices to quickly see clear pictures.
Basically that's it. It seems simple, but many people ignore the choice of size and format, which leads to the website being unable to run fast. As long as you pay attention to these links, it will not be that difficult to optimize the picture.
The above is the detailed content of How to optimize images for web. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undress AI Tool
Undress images for free
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
How to send web pages to desktop as shortcut in Edge browser?
Mar 14, 2024 pm 05:22 PM
How to send web pages to the desktop as a shortcut in Edge browser? Many of our users want to display frequently used web pages on the desktop as shortcuts for the convenience of directly opening access pages, but they don’t know how to do it. In response to this problem, the editor of this issue will share the solution with the majority of users. , let’s take a look at the content shared in today’s software tutorial. The shortcut method of sending web pages to the desktop in Edge browser: 1. Open the software and click the "..." button on the page. 2. Select "Install this site as an application" in "Application" from the drop-down menu option. 3. Finally, click it in the pop-up window
Develop web voting system using JavaScript
Aug 09, 2023 pm 01:30 PM
Using JavaScript to develop a web voting system Abstract: With the rapid development of the Internet, online voting has become a convenient and fast way to collect public opinions and make decisions. This article will introduce the use of JavaScript to develop a simple web voting system, which enables users to select options and submit votes. Introduction: A web voting system is a program that displays multiple options on a web page and allows users to choose. It can be used in many scenarios, such as election voting, product surveys, opinion collection, etc. This article
How to set up web page automatic refresh
Oct 26, 2023 am 10:52 AM
To set the automatic refresh of a web page, you can use the HTML "meta" tag, the JavaScript "setTimeout" function, the "setInterval" function or the HTTP "Refresh" header. Detailed introduction: 1. Use the "meta" tag of HTML. In the "<head>" tag of the HTML document, you can use the "meta" tag to set the automatic refresh of the web page; 2. The "setTimeout" function of JavaScript, etc.
What to do if the web page cannot be accessed
Sep 06, 2023 am 09:36 AM
Solutions to inaccessible web pages include checking the network connection, clearing the browser cache, checking the web page address, trying to use other browsers, checking the server status, checking the domain name resolution, checking the firewall and security settings and contacting the website administrator. Detailed introduction: 1. Check the network connection to ensure that the network connection is normal. You can try to open other web pages or use other devices to access to determine whether it is a network connection problem. If other web pages can be accessed normally, it may be a problem with the web page; 2. Clear the browser cache. The browser cache may cause the web page to fail to load, etc.
How to open php on the web page
Mar 22, 2024 pm 03:20 PM
Executing PHP code in a web page requires ensuring that the web server supports PHP and is properly configured. PHP can be opened in three ways: * **Server environment:** Place the PHP file in the server root directory and access it through the browser. * **Integrated Development Environment: **Place PHP files in the specified web root directory and access them through the browser. * **Remote Server:** Access PHP files hosted on a remote server via the URL address provided by the server.
What should I do if the images on the webpage cannot be loaded? 6 solutions
Mar 15, 2024 am 10:30 AM
Some netizens found that when they opened the browser web page, the pictures on the web page could not be loaded for a long time. What happened? I checked that the network is normal, so where is the problem? The editor below will introduce to you six solutions to the problem that web page images cannot be loaded. Web page images cannot be loaded: 1. Internet speed problem The web page cannot display images. It may be because the computer's Internet speed is relatively slow and there are more softwares opened on the computer. And the images we access are relatively large, which may be due to loading timeout. As a result, the picture cannot be displayed. You can turn off the software that consumes more network speed. You can go to the task manager to check. 2. Too many visitors. If the webpage cannot display pictures, it may be because the webpages we visited were visited at the same time.
Possible reasons why the network connection is normal but the browser cannot access the web page
Feb 19, 2024 pm 03:45 PM
The browser cannot open the web page but the network is normal. There are many possible reasons. When this problem occurs, we need to investigate step by step to determine the specific cause and solve the problem. First, determine whether the webpage cannot be opened is limited to a specific browser or whether all browsers cannot open the webpage. If only one browser cannot open the web page, you can try to use other browsers, such as Google Chrome, Firefox, etc., for testing. If other browsers are able to open the page correctly, the problem is most likely with that specific browser, possibly
What to do if the webpage cannot be opened
Feb 21, 2024 am 10:24 AM
How to solve the problem of web pages not opening With the rapid development of the Internet, people increasingly rely on the Internet to obtain information, communicate and entertain. However, sometimes we encounter the problem that the web page cannot be opened, which brings us a lot of trouble. This article will introduce you to some common methods to help solve the problem of web pages not opening. First, we need to determine why the web page cannot be opened. Possible reasons include network problems, server problems, browser settings problems, etc. Here are some solutions: Check network connection: First, we need
