本文介绍了PHP实现图片压缩的两种方法，读者可以根据具体应用参考或加以改进，以适应自身应用需求！废话不多说，主要代码部分如下：
实例1：
PHP;">
600?600:$width)*0.9;
$new_height =($height>600?600:$height)*0.9;
switch($type){
case 1:
$giftype=check_gifcartoon($imgsrc);
if($giftype){
header('Content-Type:image/gif');
$image_wp=imagecreatetruecolor($new_width,$new_height);
$image = imagecreatefromgif($imgsrc);
imagecopyresampled($image_wp,$image,$new_width,$new_height,$width,$height);
imagejpeg($image_wp,$imgdst,75);
imagedestroy($image_wp);
}
break;
case 2:
header('Content-Type:image/jpeg');
$image_wp=imagecreatetruecolor($new_width,$new_height);
$image = imagecreatefromjpeg($imgsrc);
imagecopyresampled($image_wp,$height);
imagejpeg($image_wp,75);
imagedestroy($image_wp);
break;
case 3:
header('Content-Type:image/png');
$image_wp=imagecreatetruecolor($new_width,$new_height);
$image = imagecreatefrompng($imgsrc);
imagecopyresampled($image_wp,75);
imagedestroy($image_wp);
break;
}
}
/**
* desription 判断是否gif动画
* @param sting $image_file图片路径
* @return boolean t 是 f 否
*/
function check_gifcartoon($image_file){
$fp = fopen($image_file,'rb');
$image_head = fread($fp,1024);
fclose($fp);
return preg_match("/".chr(0x21).chr(0xff).chr(0x0b).'NETSCAPE2.0'."/",$image_head)?false:true;
}
?>
实例2：
PHP;">
$Dw){
$Par=$Dw/$width;
$width=$Dw;
$height=$height*$Par;
IF($height>$Dh){
$Par=$Dh/$height;
$height=$Dh;
$width=$width*$Par;
}
}ElseIF($height>$Dh){
$Par=$Dh/$height;
$height=$Dh;
$width=$width*$Par;
IF($width>$Dw){
$Par=$Dw/$width;
$width=$Dw;
$height=$height*$Par;
}
}Else{
$width=$width;
$height=$height;
}
$nImg = ImageCreateTrueColor($width,$height); //新建一个真彩色画布
ImageCopyReSampled($nImg,$Img,$w,$h);//重采样拷贝部分图像并调整大小
ImageJpeg ($nImg,$Image); //以JPEG格式将图像输出到浏览器或文件
Return True;
//如果是执行生成缩略图操作则
}Else{
$w=ImagesX($Img);
$h=ImagesY($Img);
$width = $w;
$height = $h;
$nImg = ImageCreateTrueColor($Dw,$Dh);
IF($h/$w>$Dh/$Dw){ //高比较大
$width=$Dw;
$height=$h*$Dw/$w;
$IntNH=$height-$Dh;
ImageCopyReSampled($nImg,-$IntNH/1.8,$Dw,$h);
}Else{ //宽比较大
$height=$Dh;
$width=$w*$Dh/$h;
$IntNW=$width-$Dw;
ImageCopyReSampled($nImg,-$IntNW/1.8,$Dh,$h);
}
ImageJpeg ($nImg,$Image);
Return True;
}
}
?>
PHP
if($_SERVER['REQUEST_METHOD']=='POST'){
if (!is_uploaded_file($_FILES["photo"][tmp_name])){
echo "图片不存在";
exit();
}
if(!is_dir('img')){//路径若不存在则创建
mkdir('img');
}
$upfile=$_FILES["photo"];
$pinfo=pathinfo($upfile["name"]);
$name=$pinfo['basename'];//文件名
$tmp_name=$upfile["tmp_name"];
$file_type=$pinfo['extension'];//获得文件类型
$showPHPath=$path.$name;
原文链接：https://www.f2er.com/php/24142.htmlif(in_array($upfile["type"],$phtypes)){
echo "文件类型不符！";
exit();
}
if(move_uploaded_file($tmp_name,$path.$name)){
echo "成功！";
Img($showPHPath,100,800,2);
}
echo "<img src=\"".$showphpath."\" />";
}
?>
