original_string: protected function leadPNG()
  	{
  		$exif  = exif_imagetype($this->file) === IMAGETYPE_PNG;
  
  		if ($exif)
  		{
  			return $this->closeCase("png", "image/png");
  		}
  
  		return null;
  	}
code: protected function leadPNG()
  	{
  		$exif  = exif_imagetype($this->file) === IMAGETYPE_PNG;
  
  		if ($exif)
  		{
  			return $this->closeCase("png", "image/png");
  		}
  
  		return null;
  	}
code_tokens: protected function leadPNG ( ) { $ exif = exif_imagetype ( $ this -> file ) === IMAGETYPE_PNG ; if ( $ exif ) { return $ this -> closeCase ( "png" , "image/png" ) ; } return null ; }
docstring: Checks if thise file is a PNG.
  
  @return boolean|null
docstring_tokens: Checks if thise file is a PNG .