Get image files from Local Folder to display in the UI at runtime fails

I used below codes to retrieve image files from LocalFolder

Total images files is 20 in LocalFolder

The problem:

1. Only 8 images are displayed and the rest is blank.
   Why the rest can not be displayed?

Can bind the BitmapImage file to the image Control as below base on MVVM ?

Example : imageURL ="ms-appdata:///local/imgfile.jpg"

---- In XAML : PhotoView.xaml

<Image x:Name="Img" Source="{Binding ImageUrl}"  Stretch="UniformToFill"/>
<TextBlock FontSize="23" Text="{Binding Unit_Price}"  Height="23" Margin="3,1,3,0"/>  
<TextBlock FontSize="23" Text="{Binding Description}" Height="23" Width="300" Margin="1,1,1,0/>

--- In code behind: PhotoView

 ItemsViewModel itemsViewModel = null;
 ObservableCollection items = null;


itemsViewModel = new ItemsViewModel();
items = itemsViewModel.GetItems();

//-- GridViewControl
ItemsViewSource.Source = items;
ItemsGridView.SelectedItem = null; 


-------------MVVM 
--------- Model : 

class ItemViewModel : ViewModelBase
{
  private string imageurl = string.Empty;
        public string ImageUrl
        {
            get
            { return imageurl; }

            set
            {
                if (imageurl == value)
                { return; }

                imageurl = value;

                isDirty = true;
                RaisePropertyChanged("ImageUrl");
            }
        }

     private decimal unit_price = 0;
        public decimal Unit_Price
        {
            get
            { return unit_price; }

            set
            {
                if (unit_price == value)
                { return; }

                unit_price = value;
                isDirty = true;
                RaisePropertyChanged("Unit_Price");
            }
        }

}

---------- View Model 

 class ItemsViewModel : ViewModelBase
    {
        private ObservableCollection items;

        public ObservableCollection Items
        {
            get
            {
                return items;
            }

            set
            {
                items = value;
                RaisePropertyChanged("Items");
            }
        }


  public ObservableCollection GetItems()
  {
     items = new ObservableCollection();

     using (var db = new SQLite.SQLiteConnection(App.DBPath))
     {

       var query = db.Table().Where(c=> c.CompanyName == Company).OrderBy(c => c.No);

       foreach (var _item in query)
       {
         var item = new ItemViewModel()
         {
             No = _item.No,                   
             ImageUrl = "ms-appdata:///local/" + _item.PictureFilename,
             Unit_Price = _item.Unit_Price,
              Description = _item.Description

           };

              items.Add(item);
         }
      }
    return items;
  }