php上传图片生成缩略图（GD库）

首先来一段简单的php上传图片生成缩略图的详细代码，分享给大家供大家参考，具体内容如下

<?php
function createThumbnail($imageDirectory, $imageName, $thumbDirectory, $thumbWidth, $quality){
$details = getimagesize("$imageDirectory/$imageName") or die('Please only upload images.');
$type = preg_replace('@^.+(?<=/)(.+)$@', '$1', $details['mime']);
eval('$srcImg = imagecreatefrom'.$type.'("$imageDirectory/$imageName");');
$thumbHeight = $details[1] * ($thumbWidth / $details[0]);
$thumbImg = imagecreatetruecolor($thumbWidth, $thumbHeight);
imagecopyresampled($thumbImg, $srcImg, 0, 0, 0, 0, $thumbWidth, $thumbHeight,
$details[0], $details[1]);
eval('image'.$type.'($thumbImg, "$thumbDirectory/$imageName"'.
(($type=='jpeg')?', $quality':'').');');
imagedestroy($srcImg);
imagedestroy($thumbImg);
}
foreach ($_FILES["pictures"]["error"] as $key => $error) {
if ($error == UPLOAD_ERR_OK) {
$tmp_name = $_FILES["pictures"]["tmp_name"][$key];
$name = $_FILES["pictures"]["name"][$key];
move_uploaded_file($tmp_name, "data/$name");
createThumbnail("/location/of/main/image", $name, "/location/to/store/thumb", 120, 80);
//120 = thumb width :: 80 = thumb quality (1-100)
}
}
?>

接下来再为大家推荐一个实例php使用GD库上传图片以及创建缩略图，直接看代码：

GD库是PHP进行图象操作一个很强大的库。

先在php.ini里增加一行引用：extension=php_gd2.dll

重启apache，做一个测试页var_dump(gd_info());输出数据表明GD库引用成功。

图片上传页面 upload.html

<html>
<head>
<meta http-equiv='Content-Type' content='text/html; charset=utf-8'>
<title>图片上传</title>
</head>
<body>
<h1>文件上传(只允许上传jpg类型图片)</h1>
<form enctype="multipart/form-data" action="upload_img.php" method="post">
 <input name="upfile" type="file"><br><br>
 <input type="submit" value="提交">
</form>
</body>
</html>

处理页面upload_img.php

<?php
 //上传图片保存地址
 $uploadfile = "upfiles/".$_FILES['upfile']['name'];
 //缩略图保存地址
 $smallfile = "upfiles/small_".$_FILES['upfile']['name'];

 if($_FILES['upfile']['type'] != "image/jpeg")
 {
  echo '文件类型错误';
 }
 else
 {
  move_uploaded_file($_FILES['upfile']['tmp_name'],$uploadfile); //上传文件

  $dstW=200;//缩略图宽
  $dstH=200;//缩略图高

  $src_image=ImageCreateFromJPEG($uploadfile);
  $srcW=ImageSX($src_image); //获得图片宽
  $srcH=ImageSY($src_image); //获得图片高

  $dst_image=ImageCreateTrueColor($dstW,$dstH);
  ImageCopyResized($dst_image,$src_image,0,0,0,0,$dstW,$dstH,$srcW,$srcH);
  ImageJpeg($dst_image,$smallfile);

  echo '文件上传成功<br>';
  echo "<img src='$smallfile' />";
 }
?>

希望对大家学习php程序设计有所帮助，谢谢大家的支持。