1.只是显示图片

string path = 相对路径

         path =绝对路径

BitmapImage image = new BitmapImage(new Uri(path, UriKind.Absolute));
img.Source = image;

2.在另一段代码中，要删除这个图片

就需要先把图片转换成文件流，在当前读取流完时，关闭流，当要删除图片时释放资源,修改代码如下:

System.IO.FileStream m_ImageStream;
        string path;

string path = 相对路径

         path =绝对路径

BitmapImage image = new BitmapImage();
m_ImageStream = new System.IO.FileStream(path, FileMode.Open);
image.BeginInit();
image.StreamSource = m_ImageStream;
image.EndInit();

img.Source = image;

删除代码:

if (m_ImageStream != null)
            {
                m_ImageStream.Close();
                m_ImageStream.Dispose();
            }
            if (System.IO.File.Exists(path))
            {
                System.IO.File.Delete(path);
                BitmapImage i = new BitmapImage();//虽然点了删除，可是图片还显示在窗体里，这时要想重新刷新，给image控件赋值一个空的图片
                img.Source = i;
            }