C# 在图片上写字

下面的代码实现了从剪贴板取出图片，然后写上字，保存到文件

Image bmap;
IDataObject data = System.Windows.Forms.Clipboard.GetDataObject();
bmap = (Image)(data.GetData(typeof(System.Drawing.Bitmap)));
Graphics g = Graphics.FromImage(bmap); 
SolidBrush drawBrush = new SolidBrush(Color.Red);
Font drawFont = new Font("Arial", 10, FontStyle.Bold, GraphicsUnit.Millimeter);
int xPos = bmap.Height - ( bmap.Height-25 );
int yPos = 3; 
g.DrawString ("zydzydyzydydydyyydydy", drawFont, drawBrush, xPos, yPos); 
string sPicPath = "d:\\filename.jpg";string sPreFix = "d:\\xxx"; 
Image smBmap ; 
smBmap = bmap.GetThumbnailImage(bmap.Width, bmap.Height, null, System.IntPtr.Zero); 
smBmap.Save(sPicPath, System.Drawing.Imaging.ImageFormat.Jpeg); 
bmap.Save(sPreFix + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
bmap = null;
smBmap = null;