如何用PHP实现CMS系统的自动生成缩略图功能

// 获取上传的图片文件
$uploadedFile = $_FILES['file']['tmp_name'];
$uploadDir = 'path/to/upload/directory/';
$uploadPath = $uploadDir . basename($_FILES['file']['name']);

// 保存上传的图片文件
move_uploaded_file($uploadedFile, $uploadPath);

// 设置缩略图的宽度和高度
$thumbWidth = 200;
$thumbHeight = 150;

// 创建一个空的画布
$thumbImage = imagecreatetruecolor($thumbWidth, $thumbHeight);

// 读取原始图片
$originalImage = imagecreatefromjpeg($uploadPath);

// 将原始图片缩放到指定尺寸
imagecopyresized($thumbImage, $originalImage, 0, 0, 0, 0, $thumbWidth, $thumbHeight, imagesx($originalImage), imagesy($originalImage));

// 保存缩略图
$thumbPath = $uploadDir . 'thumbnail_' . $_FILES['file']['name'];
imagejpeg($thumbImage, $thumbPath);

// 释放图片内存
imagedestroy($thumbImage);
imagedestroy($originalImage);

// 获取缩略图的路径
$thumbPath = $uploadDir . 'thumbnail_' . $_FILES['file']['name'];

// 在网页上显示缩略图
echo "<img src='$thumbPath' alt='Thumbnail'>";