Ben bu fonksiyonu kullanarak PNG görüntü kırpma yapıyorum. Her şey gayet iyi çalışıyor, ama ben. Png yüklemek zaman, görüntü arka plan rengi siyah olarak değiştirildi. İşte kodudur.

$bgimage_attribs = getimagesize($bgim_file_name);

        if($filetype3=='image/gif') 
            {
                $bgim_old = imagecreatefromgif($bgim_file_name); 
            }   
        else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))  
            {
                 $bgim_old = imagecreatefromjpeg($bgim_file_name);
            }
          else  if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
            {
                 $bgim_old = imagecreatefrompng($bgim_file_name);
            }

        $bgth_max_width =265; //for Album image
        $bgth_max_height =150;
        $bgratio = ($bgwidth > $bgheight) ? $bgth_max_width/$bgimage_attribs[0] : $bgth_max_height/$bgimage_attribs[1];

        $bgth_width =265;//$image_attribs[0] * $ratio; 
        $bgth_height =150;//$image_attribs[1] * $ratio;

        $bgim_new = imagecreatetruecolor($bgth_width,$bgth_height); 
        imageantialias($bgim_new,true); 
        $bgth_file_name = "partners_logs/250x150/$Attachments3";
        imagecopyresampled($bgim_new,$bgim_old,0,0,0,0,$bgth_width,$bgth_height, $bgimage_attribs[0], $bgimage_attribs[1]);
        if($filetype3=='image/gif') 
            {
                imagegif($bgim_new,$bgth_file_name,100);
                //$bgim_old = imagegif($bgim_file_name); 
            }   
        else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))  
            {
                 imagejpeg($bgim_new,$bgth_file_name,100);
            }
          else  if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
            {
                 imagepng($bgim_new,$bgth_file_name,9);
            }           `

Hatta ben de böyle çalıştı

/************************************Resizing the image 80*60****************/
        $path3="partners_logs";
        $filetype3=$_FILES["pimage"]["type"];
        $bgim_file_name = $path3."/".$Attachments2; 
        $bgimage_attribs = getimagesize($bgim_file_name);

        if($filetype3=='image/gif') 
            {
                $bgim_old = imagecreatefromgif($bgim_file_name); 
            }   
        else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))  
            {
                 $bgim_old = imagecreatefromjpeg($bgim_file_name);
            }
          else  if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
            {
                 $bgim_old = imagecreatefrompng($bgim_file_name);
                 imageAlphaBlending($bgim_old, true);

imageSaveAlpha($bgim_old, true); }

        $bgth_max_width =265; //for Album image
        $bgth_max_height =150;
        $bgratio = ($bgwidth > $bgheight) ? $bgth_max_width/$bgimage_attribs[0] : $bgth_max_height/$bgimage_attribs[1];

        $bgth_width =265;//$image_attribs[0] * $ratio; 
        $bgth_height =150;//$image_attribs[1] * $ratio;

        $bgim_new = imagecreatetruecolor($bgth_width,$bgth_height); 
        imageantialias($bgim_new,true); 
        $bgth_file_name = "partners_logs/250x150/$Attachments2";
        imagecopyresampled($bgim_new,$bgim_old,0,0,0,0,$bgth_width,$bgth_height, $bgimage_attribs[0], $bgimage_attribs[1]);
        if($filetype3=='image/gif') 
            {
                imagegif($bgim_new,$bgth_file_name,100);
                //$bgim_old = imagegif($bgim_file_name); 
            }   
        else if(($filetype3=='image/pjpeg') || ($filetype3=='image/jpeg'))  
            {
                 imagejpeg($bgim_new,$bgth_file_name,100);
            }
          else  if(($filetype3=='image/png') || ($filetype3=='image/x-png'))
            {
                 imagepng($bgim_new,$bgth_file_name,9);
                   //set the background color to your choice, paramters are int values of red,green and blue  

imagecolorallocate($bgim_new,0xFF,0xFF,0xFF); }
/******End Resize of 80*60*********/