引用命名空间：
using System.IO;
using System.IO.IsolatedStorage;
using System.Windows.Media.Imaging;
using System.Windows.Resources;
using Microsoft.Phone.Tasks;
using Microsoft.Xna.Framework.Media;
关心：Microsoft.Xna.Framework.Media;仅当你要把图片保存到媒体库的时候才需要添加引用。
对于很多应用，向隔离存储空间读取、保存图片文件是很常见的任务。在WP7中，你还可以保存、读取媒体库中的图片。
一般情况下我们使用类IsolatedStorageFileStream进行读、写、创建文件等操作。对于图片，最大的不同就是使用类BitmapImage和类WriteableBitmap.
保存Image：
private void btSaveImage_Click(object sender, RoutedEventArgs e)
{
String strTempJPEG = "iamge111.png";
using(IsolatedStorageFile iso=IsolatedStorageFile.GetUserStoreForApplication ())
{
if (iso.FileExists (strTempJPEG ))
{
iso.DeleteFile(strTempJPEG );
}
using(IsolatedStorageFileStream isostream=iso.CreateFile(strTempJPEG))
{
StreamResourceInfo sri = null;
Uri uri = new Uri(strTempJPEG ,UriKind.Relative);
sri = Application.GetResourceStream(uri);
BitmapImage bitmap = new BitmapImage();
bitmap.SetSource(sri.Stream );
WriteableBitmap wb = new WriteableBitmap(bitmap);
Extensions.SaveJpeg(wb ,isostream,wb.PixelWidth,wb.PixelHeight,0,85);
isostream.Close();
}
}
}
读取Image：
private void btScanImage_Click(object sender, RoutedEventArgs e)
{
BitmapImage bitmap = new BitmapImage();
using(IsolatedStorageFile iso=IsolatedStorageFile.GetUserStoreForApplication ())
{
using(IsolatedStorageFileStream isostream=iso.OpenFile ("iamge111.png",FileMode.Open ,FileAccess.Read ))
{
bitmap.SetSource(isostream);
this.image.Height = bitmap.PixelHeight;
this.image.Width = bitmap.PixelWidth;
}
}
this.image.Source = bitmap;
}