Windows Mobile 7.1 displaying camera photos

Hi,

I have used the Windows Mobile 7.1 new camera functions to successfully take and store pictures as defined in the MSDN examples.

string fileName = _displayedJob.Worknumber + "_" + savedCounter.ToString() + ".jpg";
library.SavePictureToCameraRoll(fileName, e.ImageStream);

I also save the image to Isolated Strorage again using the MSDN example code - the vital bit seems to be :-

using (IsolatedStorageFile isStore = IsolatedStorageFile.GetUserStoreForApplication())
{
using (IsolatedStorageFileStream targetStream = isStore.OpenFile(fileName, FileMode.Create, FileAccess.Write))
{
// Initialize the buffer for 4KB disk pages.
byte[] readBuffer = new byte[4096];
int bytesRead = -1;
// Copy the image to isolated storage.
while ((bytesRead = e.ImageStream.Read(readBuffer, 0, readBuffer.Length)) > 0)
{
targetStream.Write(readBuffer, 0, bytesRead);
}
}
}

I then store the filename used above.  Later I have a listbox picture viewer - the idea is to show thumbnails of all pictures taken using the filename to identify the pictures.  For testing I am using :-
ImageSource testImageSource = new BitmapImage(new Uri(_displayedJob.Pictures[0], UriKind.Relative));
lblPicture1.Text = _displayedJob.Pictures[0];
imgTest.Source = testImageSource;

But I don't see an image at all - what am I missing?