Two examples of image compression in PHP

/**
* desription compressed image
* @param sting $imgsrc image path
* @param string $imgdst save path after compression
*/
function image_png_size_add($imgsrc,$imgdst){
  list($width,$height,$type)=getimagesize($imgsrc);
  $new_width = ($width>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, 0, 0, 0, 0, $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, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
      imagejpeg($image_wp, $imgdst,75);
      imagedestroy($image_wp);
      break;
    case 3:
      header('Content-Type:image/png');
      $image_wp=imagecreatetruecolor($new_width, $new_height);
      $image = imagecreatefrompng($imgsrc);
      imagecopyresampled($image_wp, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
      imagejpeg($image_wp, $imgdst,75);
      imagedestroy($image_wp);
      break;
  } // bbs.it-home.org
}
/**
* desription determines whether it is a gif animation
* @param sting $image_file image path
* @return boolean t yes f no
*/
function check_gifcartoon($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;
}
?>

Example 2:

/*
Function: Adjust image size or generate thumbnails
Return: True/False
Parameters:
 $Image The image that needs to be adjusted (including path)
 $Dw=450 when adjusting Maximum width; absolute width when thumbnailing
 $Dh=450 Maximum height when adjusting; absolute height when thumbnailing
 $Type=1 1, adjust size; 2, generate thumbnail
$path='img/';/ /path
$phtypes=array(
 'img/gif',
 'img/jpg',
 'img/jpeg',
 'img/bmp',
 'img/pjpeg',
 'img/x-png '
);
Function Img($Image,$Dw=450,$Dh=450,$Type=1){
 IF(!File_Exists($Image)){
 Return False;
 }
 //Generate if necessary Thumbnail, copy the original image and re-assign it to $Image
 IF($Type!=1){
 Copy($Image,Str_Replace(".","_x.",$Image));
 $Image= Str_Replace(".","_x.",$Image);
 }
 //Get the file type and create different objects according to different types
 $ImgInfo=GetImageSize($Image);
 Switch($ImgInfo[2 ]){
 Case 1:
 $Img = @ImageCreateFromGIF($Image);
 Break;
 Case 2:
 $Img = @ImageCreateFromJPEG($Image);
 Break;
 Case 3:
 $Img = @ImageCreateFromPNG( $Image);
 Break;
 }
 //If the object is not created successfully, it means it is not an image file
 IF(Empty($Img)){
 //If there is an error when generating the thumbnail, you need to delete it Copied file
 IF($Type!=1){Unlink($Image);}
 Return False;
 }
 //If the resize operation is performed, then
 IF($Type==1){
 $w= ImagesX($Img);
 $h=ImagesY($Img);
 $width = $w;
 $height = $h;
 IF($width>$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,$height); //Create a new true color canvas
 ImageCopyReSampled($nImg,$Img,0,0,0,0,$width,$height,$w,$ h);//Resample copy part of the image and resize it
 ImageJpeg ($nImg,$Image); //Output the image to the browser or file in JPEG format
 Return True;
 //If you are performing a thumbnail generation operation Then
 }Else{
 $w=ImagesX($Img);
 $h=ImagesY($Img);
 $width = $w;
 $height = $h;
 $nImg = ImageCreateTrueColor($Dw,$Dh );
 IF($h/$w>$Dh/$Dw){ //The height ratio is large
 $width=$Dw;
 $height=$h*$Dw/$w;
 $IntNH=$height- $Dh;
 ImageCopyReSampled($nImg, $Img, 0, -$IntNH/1.8, 0, 0, $Dw, $height, $w, $h);
 }Else{ //The width ratio is large
 $height= $Dh;
 $width=$w*$Dh/$h;
 $IntNW=$width-$Dw;
 ImageCopyReSampled($nImg, $Img, -$IntNW/1.8, 0, 0, 0, $width, $Dh, $w, $h);
 }
 ImageJpeg ($nImg,$Image);
 Return True;
 }
}
?>


   < ;td>  
Upload pictures
 The file types allowed to be uploaded are:< ;/form>
 if($_SERVER['REQUEST_METHOD']=='POST'){
 if (!is_uploaded_file($_FILES["photo"][tmp_name])){
 echo "The picture is not Exists";
 exit();
 }
 if(!is_dir('img')){//If the path does not exist, create it
 mkdir('img');
 }
 $upfile=$_FILES["photo" ];
 $pinfo=pathinfo($upfile["name"]);
 $name=$pinfo['basename'];//File name
 $tmp_name=$upfile["tmp_name"];
 $file_type=$ pinfo['extension'];//Get the file type
 $showphpath=$path.$name;

 if(in_array($upfile["type"],$phtypes)){
 echo "The file type does not match! ";
 exit();
 }
 if(move_uploaded_file($tmp_name,$path.$name)){
 echo "Success! ";
 Img($showphpath,100,800,2);
 }
 echo "";
 }
?>

< ;/html>