小尺寸png背景变黑色

$path = "D:\\pic\\";

korea_process_avatar($path . 'smile1.png',$path . 'kk.png');

function korea_process_avatar($avatar = '', $destfile = '') {

        $filename = @imagecreatefrompng($avatar);

        $width = ImageSx($filename);

        $height = ImageSy($filename);

        $new_width = 10;

        $new_height = 10;

        $image_p = @imagecreatetruecolor($new_width, $new_height);

        @imagealphablending($image_p, false);

@imagesavealpha($image_p, true);

@imagealphablending($filename, false);

@imagesavealpha($filename, true);       

//生成尺寸小的png图片，背景会变黑，函数bug

        @fastimagecopyresampled($image_p, $filename, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

//改为本函数即可解决

        @imagecopyresampled($image_p, $filename, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

       

        imagepng($image_p, $destfile, 3);

        imagedestroy($image_p);

        imagedestroy($image);

    }