// 验证码生成代码示例
session_start();
$code = rand(1000,9999);
$_SESSION['captcha'] = $code;

$image = imagecreatetruecolor(100, 30);
$bg_color = imagecolorallocate($image, 255, 255, 255);
$text_color = imagecolorallocate($image, 0, 0, 0);
imagefill($image, 0, 0, $bg_color);
imagestring($image, 5, 10, 5, $code, PHP商城登录界面验证码无法加载的修复方案 $text_color);

header('Content-type: image/jpeg');
imagejpeg($image);
imagedestroy($image);