Downloading files from wepage and saving on android ,Download from webpage, and open it on android

Hello,

I would like to have option like that:

Someone who click button "download image": then program will download image, and will open image not in Unity, by in your local program to images.

I have code like that:

     private IEnumerator TestDownload()
     {
         WWW www = new WWW("https://www.szerokikadr.pl/public/repozytorium/poradnik/201211/3/160_732388c2.jpg");
         yield return www;
 
         while (!www.isDone) {
 
             Debug.Log( www.progress ) ;
             yield return null;
         }
 
     
         string savePath = Application.persistentDataPath + "/picture.jpg";
 
         byte[] bytes = www.bytes;
 
         File.WriteAllBytes(savePath, bytes);
         Application.OpenURL(savePath);
 }

But it shows me that this file doesn't exist.

I would be really grateful if someone could help me : ) Thank you in advice, and have a nice day.