public function toPNG()
    {
        $this->extension = 'png';
        $this->type = IMAGETYPE_PNG;
        $this->mimetype = Utils::getMimetypeByImageType(IMAGETYPE_PNG);
        return $this;
    }
public function toPNG()
    {
        $this->extension = 'png';
        $this->type = IMAGETYPE_PNG;
        $this->mimetype = Utils::getMimetypeByImageType(IMAGETYPE_PNG);
        return $this;
    }
public function toPNG ( ) { $ this -> extension = 'png' ; $ this -> type = IMAGETYPE_PNG ; $ this -> mimetype = Utils :: getMimetypeByImageType ( IMAGETYPE_PNG ) ; return $ this ; }
Changes output format to PNG.

@access public
@return \GImage\Image
Changes output format to PNG .