laravel - How to add text to an image in php and return the image to browser

one text

I'm using following code to create captcha image:

create function code:

public function create(){
    $this->image=imagecreatetruecolor($this->width,$this->height);
    
    for($i=0,$x=5;$i<$this->length;$i++,$x+=20){
        $angel=[mt_rand(3,35),mt_rand(350,360)];
        $y=mt_rand(30,35);
        $textColor=imagecolorallocate($this->image, rand(0, 255), rand(0, 255), rand(0, 255));
        imagettftext($this->image, $this->fontSize, $angel[mt_rand(0,1)], $x, $y, $textColor, $font, $characters[$i]);
    }

    return response(imagepng($this->image), 200, ["Content-type" => "image/png"]);
}

controller file:

public function getCaptcha(){
    if (ob_get_contents()) {
        ob_clean();
    }
    return $captcha->create();
}

sometimes it shows error :

The byte stream was erroneous according to the character encoding that was declared. The character encoding declaration may be incorrect. error image

no error image