C# 多张图片合成的问题

 //首先给出一个函数；用来将图片保存到内存中
private Image ReturnImage(string strPhotoPath)
{
FileStream fstream = new FileStream(strPhotoPath, FileMode.OpenOrCreate, FileAccess.Read);
byte[] byData = new byte[fstream.Length];
fstream.Read(byData, 0, System.Convert.ToInt32(fstream.Length));
fstream.Close();

System.IO.MemoryStream stream = new System.IO.MemoryStream(byData, true);
//stream.Write(byData, 0, byData.Length);//此句可省略，上一句构造函数已经将字节流塞进流了
Bitmap bmp = new Bitmap(stream);
System.Drawing.Image image = bmp;
return bmp;
}

private void Fold_Click(object sender, EventArgs e)
{
string str0 = "BOR/01/CAR.JPG";//像框文件的路径
string str1 = "BOR/01/A.JPG";//照片文件的全路径
string str2 = "BOR/01/L.JPG";//照片文件的全路径
string str3 = "BOR/01/A.JPG";//照片文件的全路径
string str4 = "BOR/01/2.JPG";//照片文件的全路径
string str5 = "BOR/01/6.JPG";//照片文件的全路径
string str6 = "BOR/01/3.JPG";//照片文件的全路径
Image img0 = ReturnImage(str0);
Image img1 = ReturnImage(str1);
System.Drawing.Image newImage = img0.GetThumbnailImage(90, 22, null, new IntPtr());

//Graphics g = Graphics.FromImage(img0);这句话改成如下，以控制背景图片尺寸
Bitmap bmap = new Bitmap(90,22);
Graphics g = Graphics.FromImage(bmap);

g.DrawImage(newImage, 0, 0, 90, 22);
g.DrawImage(img1, 13, 4, 11, 14);
img1 = ReturnImage(str2);
g.DrawImage(img1, (float)29.5, 4, 11, 14);
img1 = ReturnImage(str3);
g.DrawImage(img1, (float)41.5, 4, 11, 14);
img1 = ReturnImage(str4);
g.DrawImage(img1, (float)53.5, 4, 11, 14);
img1 = ReturnImage(str5);
g.DrawImage(img1, (float)65.5, 4, 11, 14);
img1 = ReturnImage(str6);
g.DrawImage(img1, (float)77.5, 4, 11, 14);
this.pictureBox1.Image = img0;
}