What potential issues can arise when using PHP to generate and serve images, such as in the case of creating a Captcha?

One potential issue when using PHP to generate and serve images for a Captcha is that the images may not be properly cached, leading to increased server load and slower performance. To solve this, you can use PHP's `header()` function to set appropriate caching headers for the image. 

// Set appropriate caching headers for the image
header('Cache-Control: no-cache, no-store, must-revalidate');
header('Pragma: no-cache');
header('Expires: 0');

Keywords

GD library image processing memory consumption security vulnerabilities Captcha generation

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