<ListView Grid.Row="1" Grid.Column="0" Background="Transparent"
          ItemsSource="{Binding MyViewModelObservableCollection}"

          AllowDrop = "True"

          Drop = "{Binding TheDropHandlerInTheViewModel, PassTheDropEventArgs}"

          DragOver = "{Binding TheDragOverHandlerInTheViewModel, PassTheDrageEventArgs}">

</ListView>

private void ImagePanel_Drop(object sender, DragEventArgs e)
{

  if (e.Data.GetDataPresent(DataFormats.FileDrop))
  {
    // можно же перетянуть много файлов, так что....
    string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);

    // делаешь что-то
  }
}

<StackPanel Name="ImagePanel" Drop="ImagePanel_Drop" AllowDrop="true">
    ...
</StackPanel>

Drop="ImagePanel_Drop" AllowDrop="true"

<Grid>
    <ListBox ItemsSource="{Binding Items}"
             dd:DragDrop.IsDropTarget="True"
             dd:DragDrop.DropHandler="{Binding}"
             >

    </ListBox>
</Grid>

public class MainViewModel : ViewModelBase, IDropTarget
{

    public ObservableCollection<string> Items { get; set; }

    public MainViewModel()
    {
        Items = new ObservableCollection<string>();
    }

    public void DragOver(IDropInfo dropInfo)
    {
        dropInfo.DropTargetAdorner = DropTargetAdorners.Insert;

        var dataObject = dropInfo.Data as IDataObject;

        dropInfo.Effects = dataObject != null && dataObject.GetDataPresent(DataFormats.FileDrop)
            ? DragDropEffects.Copy
            : DragDropEffects.Move;
    }

    public void Drop(IDropInfo dropInfo)
    {
        var dataObject = dropInfo.Data as DataObject;
        if (dataObject != null && dataObject.ContainsFileDropList())
        {
            var files = dataObject.GetFileDropList();
            foreach (var file in files)
            {
                Items.Add(file);

            }
        }
    }
}