What are the potential pitfalls of using PNG images with transparency in PHP, especially when targeting Internet Explorer?

When using PNG images with transparency in PHP, especially when targeting Internet Explorer, the potential pitfall is that older versions of Internet Explorer do not support PNG transparency correctly. To solve this issue, you can use a PHP script to check the user's browser and serve a different image format, such as GIF, for Internet Explorer browsers that do not support PNG transparency. 

<?php
$user_agent = $_SERVER['HTTP_USER_AGENT'];

if (strpos($user_agent, 'MSIE') !== false) {
    // Serve a GIF image instead of PNG for Internet Explorer
    header('Content-Type: image/gif');
    readfile('image.gif');
} else {
    // Serve the PNG image for other browsers
    header('Content-Type: image/png');
    readfile('image.png');
}
?>

Keywords

PNG images transparency Internet Explorer compatibility alpha channel

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