How to implement a MultiSelected Photo page in WP8? - windows-phone-8

Question

I know that now in Windows Phone 8.1 and Windows 8.1, it's easy to choose multi-photos using FileOpenPicker.
But in Windows Phone 8.0, only native code have access to the API, so if we have to choose multi-photos to do something(that is ,like uploading), we have to implemenet it by toolkit:LongListMultiSelector .
By doing this, I have a performance problem.
Here is the XAML:
<ScrollViewer x:Name="ScrowllViewAlbum" HorizontalAlignment="Left" Height="500" VerticalAlignment="Top" Width="458" >
<toolkit:LongListMultiSelector
x:Name="AlbumList"
IsGroupingEnabled="False"
GridCellSize="100,100"
LayoutMode="Grid"
HideEmptyGroups="True"
IsSelectionEnabled="False"
EnforceIsSelectionEnabled="False"
CacheMode="BitmapCache"
ItemsSource="{Binding}"
Width="459"
ItemTemplate="{StaticResource AllPhotoTemplete}" Background="Black"
/>
</ScrollViewer>
and in ViewModel:
public void LoadAllPhotos()
{
Allphotos = new ObservableCollection<BitmapImage>();
MediaLibrary medialib = new MediaLibrary();
PictureCollection pics = medialib.Pictures;
if (pics.Count!=0)
{
BitmapImage image = new BitmapImage();
foreach(var pic in pics)
{
Stream stream = pic.GetImage();
image.SetSource(stream);
Allphotos.Add(image);
}
}
}
However, during the debug, it throw out an exception of no insufficient memory.
Can you give me some idea to optimize the function?
Thanks :-)

Answer 1

There is no other way then implement the picker yourself.
since you are only loading the images for a preview, only load the thumbnail like:
var image = new BitmapImage();
image.SetSource(pic.GetThumbnail());