将一张图片生成多张缩略图并保存

$filename="des_big.jpg";
list($src_w,$src_h,$imagetype)=getimagesize($filename);
$mime=image_type_to_mime_type($imagetype);
//echo $mime;//输出为imae/jpeg
$createFun=str_replace("/","createfrom",$mime);
//imagejpeg()
$outFun=str_replace("/",null,$mime);
$src_image=$createFun($filename);
$dst_50_image=imagecreatetruecolor(50,50);
$dst_220_image=imagecreatetruecolor(220,220);
$dst_350_image=imagecreatetruecolor(350,350);
$dst_800_image=imagecreatetruecolor(800,800);
imagecopyresampled($dst_50_image,$src_image,0,0,0,0,50,50,$src_w,$src_h);
imagecopyresampled($dst_220_image,$src_image,0,0,0,0,220,220,$src_w,$src_h);
imagecopyresampled($dst_350_image,$src_image,0,0,0,0,350,350,$src_w,$src_h);
imagecopyresampled($dst_800_image,$src_image,0,0,0,0,800,800,$src_w,$src_h);

$outFun($dst_50_image,"uploads/image_50/".$filename);
$outFun($dst_220_image,"uploads/image_220/".$filename);
$outFun($dst_350_image,"uploads/image_350/".$filename);
$outFun($dst_800_image,"uploads/image_800/".$filename);
imagedestroy($src_image);
imagedestroy($dst_50_image);
imagedestroy($dst_220_image);
imagedestroy($dst_350_image);
imagedestroy($dst_800_image);

image_type_to_mime_type — 取得 getimagesize，exif_read_data，exif_thumbnail，exif_imagetype 所返回的图像类型的 MIME 类型

imagecreatefromjpeg — 由文件或 URL 创建一个新图象。
说明
resource imagecreatefromjpeg ( string $filename )

imagecreatefromjpeg() 返回一图像标识符，代表了从给定的文件名取得的图像。