php怎么将内容转换成图片

$imgstr = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==';

         if 
          (!preg_match(
         '/data:([^;]*);base64,(.*)/'
         , 
         $imgstr
         , 
         $matches
         )) {
        
 
           
         die
         (
         "error"
         );
        
 
         }
        
 
           
        
 
         $content 
          = 
         base64_decode
         (
         $matches
         [2]);
        
 
         header(
         'Content-Type: '
         .
         $matches
         [1]);
        
 
         header(
         'Content-Length: '
         .
         strlen
         (
         $content
         ));
        
 
           
        
 
         echo 
          $content
         ;
        
 
         die
         ;

       $imgdata 
          = 
         substr
         (
         $imgstr
         ,
         strpos
         (
         $imgstr
         ,
         ","
         ) + 1);
        
 
         $decodedData 
          = 
         base64_decode
         (
         $imgdata
         );
        
 
         file_put_contents
         (
         '11.png'
         ,
         $decodedData 
          );