php图片上传并生成缩略图代码-PHP源码

if($_FILES['image']['size']){
if($_FILES['image']['type'] == "image/pjpeg"){
$im = @imagecreatefromjpeg($_FILES['image']['tmp_name']);
$n_bmp.='.jpg';
}elseif($_FILES['image']['type'] == "image/x-png"){
$im = @imagecreatefrompng($_FILES['image']['tmp_name']);
$n_bmp.='.png';
}elseif($_FILES['image']['type'] == "image/gif"){
$im = @imagecreatefromgif($_FILES['image']['tmp_name']);
$n_bmp.='.gif';
}
ResizeImage($im,8888,8888,$n_bmp);
ImageDestroy ($im);
$n_tag =1;

}

function Uploadfile($str){

$save_path = './product/';//文件保存目录路径

$ext_arr = array('rar','zip','jpg','gif','png','bmp');//定义允许上传的文件扩展名

$max_size = 1000000;//最大文件大小

$file_rand ='';

$file_ext ='';

@mkdir($save_path, 0777); //更改目录权限

if ($_FILES[$str]['name']) {//有上传文件时

$file_name = $_FILES[$str]['name'];//原文件名

$tmp_name = $_FILES[$str]['tmp_name'];//服务器上临时文件名

$file_size = $_FILES[$str]['size'];//文件大小

if (@is_dir($save_path) === false) {//检查目录
alert("上传目录不存在。",'');
}

if (@is_writable($save_path) === false) {//检查目录写权限
alert("上传目录没有写权限。",'');
}

if (@is_uploaded_file($tmp_name) === false) {//检查是否已上传
alert("临时文件可能不是上传文件。",'');
}

if ($file_size > $max_size) {//检查文件大小
alert("上传文件大小超过限制。",'');
}

$temp_arr = explode(".", $file_name);//获得文件扩展名
$file_ext = array_pop($temp_arr);
$file_ext = trim($file_ext);
$file_ext = strtolower($file_ext);
$file_rand= md5(date("Y-m-d"));
if (in_array($file_ext, $ext_arr) === false) {//检查扩展名
alert("上传文件扩展名是不允许的扩展名。",'');
}

if (move_uploaded_file($tmp_name, $save_path.$file_rand.'.'.$file_ext) === false) {//移动文件
alert("上传文件失败。",'');
}
}
return $save_path.$file_rand.'.'.$file_ext;
}


function ResizeImage($im,$maxwidth,$maxheight,$name){
$width = imagesx($im);
$height = imagesy($im);
if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
if($maxwidth && $width > $maxwidth){
$widthratio = $maxwidth/$width;
$RESIZEWIDTH=true;
}
if($maxheight && $height > $maxheight){
$heightratio = $maxheight/$height;
$RESIZEHEIGHT=true;
}
if($RESIZEWIDTH && $RESIZEHEIGHT){
if($widthratio <$heightratio){
$ratio = $widthratio;
}else{
$ratio = $heightratio;
}
}elseif($RESIZEWIDTH){
$ratio = $widthratio;
}elseif($RESIZEHEIGHT){
$ratio = $heightratio;
}
$newwidth = $width * $ratio;
$newheight = $height * $ratio;
if(function_exists("imagecopyresampled")){
$newim = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
}else{
$newim = imagecreate($newwidth, $newheight);
imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
}
ImageJpeg ($newim,'./product_e/'.$name);
ImageDestroy ($newim);
}else{
ImageJpeg ($im,'./product_e/'.$name);
}
}