What is the main issue the user is facing with sorting images in PHP?

The main issue the user is facing with sorting images in PHP is that they are not able to sort the images based on their creation date. To solve this issue, the user can use the `filemtime()` function in PHP to get the last modified time of the image files and then sort them accordingly.

// Get all image files in a directory
$images = glob('path/to/images/*.jpg');

// Sort the images based on their last modified time
usort($images, function($a, $b) {
    return filemtime($a) < filemtime($b);
});

// Display the sorted images
foreach($images as $image) {
    echo '<img src="' . $image . '" />';
}