private void OnAdd()
        {
            user = Serializer.DeserializeUser();
            int count  = 0;
            int number = -1;

            CurrentPicture = new Picture(uri, Title, Description);
            CurrentPicture.Validate();
            if (CurrentPicture.IsValid)
            {
                user.Pictures.Add(new Picture(uri, Title, Description));
                PictureViewModel.picturesChange(user);
                allUsers = Serializer.Deserialize();
                foreach (Users tempuser in allUsers.Users)
                {
                    if (tempuser.Username == user.Username)
                    {
                        number = count;
                    }
                    count++;
                }
                allUsers.Users[number].Pictures.Add(CurrentPicture);
                Serializer.SerializeUser(allUsers.Users[number]);
                Serializer.Serialize(allUsers);
                Title       = "";
                Description = "";
                Bitmap bitmap = (Bitmap)Bitmap.FromFile(@"C:\Users\pc\Desktop\Blok5-Projekat1\MVVM1\bin\Debug\addLogo.png", true);
                ButtonSource = BitmapConversion.BitmapToBitmapSource(bitmap);
            }
        }
        public StudentViewModel()
        {
            user          = Serializer.DeserializeUser();
            BrowseCommand = new MyICommand(OnBrowse);
            AddCommand    = new MyICommand(OnAdd);
            Bitmap bitmap = (Bitmap)Bitmap.FromFile(@"C:\Users\pc\Desktop\Blok5-Projekat1\MVVM1\bin\Debug\addLogo.png", true);

            bitmapSource = BitmapConversion.BitmapToBitmapSource(bitmap);
        }
        private void OnBrowse()
        {
            OpenFileDialog op = new OpenFileDialog();

            op.Title  = "Select a picture";
            op.Filter = "All supported graphics|*.jpg;*.jpeg;*.png|" +
                        "JPEG (*.jpg;*.jpeg)|*.jpg;*.jpeg|" +
                        "Portable Network Graphic (*.png)|*.png";
            if (op.ShowDialog() == true)
            {
                Bitmap bitmap = (Bitmap)Bitmap.FromFile(op.FileName, true);
                ButtonSource = BitmapConversion.BitmapToBitmapSource(bitmap);
                uri          = op.FileName;
            }
        }