Windows phone 7: get the name of an image which is stored in Media Libary?

Definitely you get this file name
This is the Button Click who Choose the Photo From Your Phone

private void ImgPicker_Click(object sender, RoutedEventArgs e)
        {
            PhotoResult photoresult = new PhotoResult();
            MessageBox.Show( photoresult.OriginalFileName);
        }

Just Copy And Paste this code.
In the Messagebox you Get the File Name.

or if you want to more Details About image Than Check This Referance
http://www.mindscapehq.com/blog/index.php/2012/02/28/windows-phone-7-working-with-camera-tasks/[^]
Enjoy...