code: public function getMime()
      {
          $this->absolute();
  
          //mime_content_type seems to be deprecated in some versions of PHP
          //if it does exist then lets use it
          if (function_exists('mime_content_type')) {
              return mime_content_type($this->data);
          }
  
          //if not then use the replacement funciton fileinfo
          //see: http://www.php.net/manual/en/function.finfo-file.php
          if (function_exists('finfo_open')) {
              $resource = finfo_open(FILEINFO_MIME_TYPE);
              $mime = finfo_file($resource, $this->data);
              finfo_close($finfo);
  
              return $mime;
          }
  
          //ok we have to do this manually
          //get this file extension
          $extension = strtolower($this->getExtension());
  
          //get the list of mimetypes stored locally
          $types = self::$mimeTypes;
          //if this extension exissts in the types
          if (isset($types[$extension])) {
              //return the mimetype
              return $types[$extension];
          }
  
          //return text/plain by default
          return $types['class'];
      }
docs: Returns the mime type of a file
  
  @return string