php 上传图片的函数示例

1，form表单部分

<!-- Form Area -->
<form enctype="multipart/form-data" action="uploader.php" method="post"> 
Select Image: <input type="file" name="userfile"> 
<input type="submit" value="Upload!"> 
</form> 
<!-- Form Area -->

2，上传图片文件的php代码

<?php 

# Variables
$path = "images/";  
$max_size = "200000"; 

# File
$filename = $_POST['userfile']; 

# Control
if (!isset($HTTP_POST_FILES['userfile'])) exit; 

if (is_uploaded_file($HTTP_POST_FILES['userfile']['tmp_name'])) { 

if ($HTTP_POST_FILES['userfile']['size']>$max_size) {  
echo "文件太大，超过了上传文件的最大限制。The Max File Size is $max_size KB<br>n";  
exit;  
} 

# Type Control
if ( 
   ($HTTP_POST_FILES['userfile']['type']=="image/gif")   ||          
   ($HTTP_POST_FILES['userfile']['type']=="image/jpg")   ||   
   ($HTTP_POST_FILES['userfile']['type']=="image/bmp")   || 
   ($HTTP_POST_FILES['userfile']['type']=="image/png")   || 
   ($HTTP_POST_FILES['userfile']['type']=="image/jpeg") 
) 
{ 

# If File Exist
if (file_exists($path . $HTTP_POST_FILES['userfile']['name']))  
{  
echo "同名的文件已存在。<br>";  
exit;  
} 

$res = copy($HTTP_POST_FILES['userfile']['tmp_name'], $path . 

$HTTP_POST_FILES['userfile']['name']); 
if (!$res){  
echo "上传失败！<br>";  
exit;  
}  
else{  
echo "上传成功!<br>";  
} 

echo "File Name: ".$HTTP_POST_FILES['userfile']['name']."<br>"; 
echo "File Size: ".$HTTP_POST_FILES['userfile']['size']." bytes<br>"; 
echo "File Type: ".$HTTP_POST_FILES['userfile']['type']."<br>"; 
echo "<a href=$path".$HTTP_POST_FILES['userfile']['name'].">View Image</a>"; 
}  
else  
{ 
echo "错误的文件类型<br>";  
exit;  
} 
} 
?>

注意：
在php5以后的代码，已经不再使用这样的方式，改用全局变量$_FILE来接收上传数据了。