php上传图片生成缩略图（GD库）

发布:smiling　来源: PHP粉丝网　添加日期：2021-07-04 00:56:59　浏览: 评论：0　

这篇文章主要介绍了php上传图片生成缩略图，还阐述了利用GD库上传图片以及创建缩略图，感兴趣的小伙伴们可以参考一下。

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' />";

}

?>