Out of memory exception in listbox

I have a listbox where I am loading some images from media library.But iam getting an exception when loading it second time or clicking back button.Here is my code.....

 public MainPage()
{
InitializeComponent();
getImages();

}
public void getImages()
{
try
{
    MediaLibrary mediaLibrary = new MediaLibrary();
    var pictures = mediaLibrary.Pictures;
    foreach (var picture in pictures)
    {
        BitmapImage image = new BitmapImage();
        image.SetSource(picture.GetImage());//out of memory exception
        img mediaImage = new img();
        mediaImage.Imgs = image;
        imageList.Items.Add(mediaImage);
    }
}
catch (Exception ex)
{

}

}
public class img
{
public img()
{ }
public BitmapImage Imgs { get; set; }
}

in Xaml...

<ScrollViewer Name="sc" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Hidden" Margin="0,422,0,43"><ListBox Name="imageList" SelectionChanged="imageList_SelectionChanged_1" Height="126"><ListBox.ItemsPanel><ItemsPanelTemplate ><StackPanel Orientation="Horizontal"></StackPanel></ItemsPanelTemplate></ListBox.ItemsPanel><ListBox.ItemTemplate><DataTemplate ><StackPanel Orientation="Horizontal"><Image Margin="10" Name="image1" Source="{Binding Imgs}" Height="150" Width="150"></Image></StackPanel></DataTemplate></ListBox.ItemTemplate></ListBox></ScrollViewer>

in getimages() method in picture.getimage() it is showing out of memory exception(I have written in code).

So pls help......I  cannot picture.getThumbnail due to some reasons...

---

dj_Fox