What should I do if the pictures uploaded by php cannot be displayed on the page?

PHP is a server-side programming language widely used for website development. It supports uploading images to the server. Uploading images is a very common feature that allows users to share their own images on the website or display images as content on the website. However, during the actual development process, you may encounter the problem that the uploaded images cannot be displayed on the page. This article will discuss the reasons why uploading images fails and provide some solutions.

1. Relative path error

PHP When uploading images, if a relative path is used to store the image, the path of the image should be calculated starting from the current page. If the files are stored in different directories, the relative paths will need to be changed accordingly. If the path is wrong, the image cannot be loaded correctly. The solution is to use absolute paths.

2. Permission issues

When PHP attempts to upload a file to the file system, if the permissions for the directory are incorrect, the upload will fail. You can use the chmod command to change the permissions of a file directory, for example, change the directory permissions to 755.

3. File size limit

The php.ini file limits the maximum size of uploaded files. If the file size exceeds the upload file size set in php.ini, the upload will fail. The upload size limit can be changed by modifying upload_max_filesize and post_max_size in php.ini.

4. Incorrect file format

When the format of the uploaded file is incorrect, such as uploading a JPG image file but specifying the PNG file content type, the upload will fail. This issue can be resolved by checking the file extension of the uploaded file and comparing it to the correct MIME type.

5. Maximum execution time limit

The file size allowed to be uploaded by PHP is related to the script execution time. If the script execution time exceeds the maximum time limit set by PHP, PHP will stop execution and the upload operation will be cancelled. The execution time can be increased by modifying max_execution_time in php.ini.

6. Memory Limitation

The size of files that PHP allows to be uploaded is also limited by the amount of memory available in the system. If the uploaded file size exceeds the system memory limit, the upload will fail. The amount of available memory can be increased by modifying memory_limit in php.ini.

Summary

Uploading images in PHP is a very common and basic operation. However, image uploads may fail due to various reasons, and this article provides some solutions for solving common problems with failed uploads. Whether it is using a more appropriate file path or modifying file permissions, modifying script execution time or memory limits, we need to solve specific problems manually. Only with the courage and patience to solve problems can we realize the full potential of the PHP toolbox.

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