PHP snippet to convert all WebP images back to original formats - works only with WordPress plugin Images to WebP

convert-webp.php

<?php

function convertWebPImages( $directory = '.' ){
	$files = glob( $directory . '/*.webp' );
	foreach( $files as $file ){
		$original_file = substr( $file, 0, -5 );
		$original_ext = pathinfo( $original_file, PATHINFO_EXTENSION );
		if( ! file_exists( $original_file ) ){
			$webp = imagecreatefromwebp( $file );
			if( $webp !== false ){
				switch( $original_ext ){
					case 'jpg':
					case 'jpeg':
						imagejpeg( $webp, $original_file, 95 );
						break;
					case 'png':
						imagepng( $webp, $original_file, 9 );
						break;
					case 'gif':
						imagegif( $webp, $original_file );
						break;
				}
				imagedestroy( $webp );
				echo '<br>Converted ' . $file;
			}else{
				echo '<br>Can not convert ' . $file;
			}
		}else{
			echo '<br>Original file exists for ' . $file;
		}
	}

	$directories = glob( $directory . '/*', GLOB_ONLYDIR );
	foreach( $directories as $subdirectory ){
		convertWebPImages( $subdirectory );
	}
}

convertWebPImages();