PHP Warning : imagewebp(): Palette image not supported by webp

Question

I am trying to create webp images from jpeg and png images using PHP but I have several errors like:
Warning: imagewebp(): Palette image not supported by webp in /var/www/html/img/

I have consulted the resource Fatal error: Paletter image not supported by webp but unless I am mistaken, it seems to me that I have already applied these recommendations.

Here is my function :

        function convertToWebP($url) {
    
        $extension = pathinfo($url, PATHINFO_EXTENSION);
        $lstat = lstat($url);
        $mtime = date('d/m/Y H:i:s', $lstat['mtime']);
    
        switch ($extension) {
            case 'jpeg' :
            case 'jpg' :
                $image = imagecreatefromjpeg($url);
                break;
    
            case 'png' :
                $image = imagecreatefrompng($url);
                imagepalettetotruecolor($image);
                imagealphablending($image, true);
                imagesavealpha($image, true);
                break;
    
            case 'gif' :
                $image = imagecreatefromgif($url);
                break;
    
            default : 
                return false;
            }
    
            imagewebp($image, 'php.webp', 80);
            imagedestroy($image);
}

I would be very grateful to have some help

PHP 7.4.3 Server version: Apache/2.4.41 (Ubuntu) Ubuntu 20.04.2 LTS

Answer 1

Thanks to Kim Hallberg's comment, I found the solution. it was enough to add the imagepalettetotruecolor function to convert the .gif files as well.