Convert WordPress Image Filename To Lowercase

WordPress by default will preserve capitalisation in filename for images. To make filenames lowercase automatically, add the following to the functions.php of your active theme.

/**
 * Convert filename to lowercase
 *
 * @author Arun Basil Lal
 * @refer https://codex.wordpress.org/Plugin_API/Filter_Reference/wp_handle_upload_prefilter
 */
function prefix_convert_filename_to_lowercase( $file ) {
	
	$image_extensions = array (
		'image/jpeg', 'image/gif', 'image/png', 'image/bmp', 'image/tiff', 'ico'
	);
	
	// Return if file is not an image file
	if ( ! in_array($file['type'],$image_extensions) ) {
		return $file;
	}
	
	$image_extension = pathinfo( $file['name'] );
	$image_name 	 = strtolower( $image_extension['filename'] );
	$file['name'] 	 = $image_name . '.' . $image_extension['extension'];
	
	return $file;
}
add_filter('wp_handle_upload_prefilter', 'prefix_convert_filename_to_lowercase', 20 );

Hello, I am Arun Basil Lal. Thank you for reading!

I am a WordPress product developer and creator of Image Attributes Pro. I am passionate about solving problems and travelling the world.