Texture file is all alpha when resizing

Hi all , I'm creating a texture :

  Texture2D takeScreenShotImage(string filePath)
     {
         Texture2D texture = null;
         byte[] fileBytes;
         if (File.Exists(filePath))
         {
             fileBytes = File.ReadAllBytes(filePath);
             texture = new Texture2D(1, 1, TextureFormat.ARGB32, false);
             texture.LoadImage(fileBytes);   
         }
     
         texture.Resize(texture.width / 2, texture.height / 2, TextureFormat.ARGB32, false); 
         Debug.Log (texture.width + " texture width" + texture.height + " texture height");
         return texture;
     }

and then turning it to sprite :

 Sprite sp1 = Sprite.Create(texture1, new Rect(0, 0, texture1.width, texture1.height), new Vector2(0.5f, 0.5f), 100, 0, SpriteMeshType.FullRect);

Without the resizing line ("texture.resize"), its works great , with the resize line, my texture is looking like that :

The file size was changed , but it all alpha ! Why ? How can I resize the texture correctly ?