yii2中验证码图片不显示

//加此代码块解决 if(function_exists('ob_clean')){ @ob_clean(); } imagecolordeallocate($image,$foreColor); header('Pragma: public'); header('Expires: 0'); header('Cache-Control: must-revalidate, post-check=0, pre-check=0'); header('Content-Transfer-Encoding: binary'); header("Content-type: image/png"); imagepng($image); imagedestroy($image);