Code:
Image im = Image.FromFile(opendialog1.fileName);
IList images = new ArrayList();
int count
=im.GetFrameCount(FrameDimension.Page);
for(int i=0; i < count; i++)
{
im.SelectActiveFrame(FrameDimension.Page, i);
MemoryStream m = new MemoryStream();
im.Save(m, ImageFormat.Bmp);
images.Add( Image.FromStream(m));
// m.SetLength(0);