‘crop_thumbnails_filename’ hook doesn’t save image

Hi there!

I’m trying to use the ‘crop_thumbnails_filename’ hook to change the name of an image file when it’s cropped. However, when I use the following code the URL being output on the frontend changes but it no longer displays the image.

function changeCroppedFileName($file) {
	$filePathInfo = pathinfo($file);

	$filename = $filePathInfo['filename'];
	$extension = $filePathInfo['extension'];

	$date = new DateTime();
	$timestamp = $date->getTimestamp();

	$newPath = $filename.'-'.$timestamp.'.'.$extension;

	return $newPath;
}
add_filter( 'crop_thumbnails_filename', 'changeCroppedFileName' );

Is there something else I need to do to save the image with the new URL?