上传图片文件，生成缩略图，并写上版权信息

private void Button1_Click(object sender, System.EventArgs e)
{
if(File1.PostedFile.FileName!=null)
{
string namestr = Path.GetFileName(File1.PostedFile.FileName);//提取文件名
File1.PostedFile.SaveAs(Server.MapPath(".")+@"\"+namestr);
Image2.Visible=true;
Image2.ImageUrl=Server.MapPath(".")+@"\"+namestr;
System.Drawing.Image image,aNewImage;
image=System.Drawing.Image.FromStream(File1.PostedFile.InputStream);
decimal width=image.Width;
decimal height=image.Height;
int newwidth,newheight;
if(width>height)
{
newwidth=150;
newheight=(int)(height/width*150);
}
else
{
newheight=150;
newwidth=(int)(width/height*150);
}
aNewImage=image.GetThumbnailImage(newwidth,newheight,null,IntPtr.Zero);
Bitmap output=new Bitmap(aNewImage);
Graphics g=Graphics.FromImage(output);
g.DrawString(TextBox1.Text.Trim(),new Font("Courier New", 9),new SolidBrush(Color.Red),60,60);//写版权信息及文本格式及位置
output.Save(Server.MapPath(".")+@"\s_"+namestr,System.Drawing.Imaging.ImageFormat.Jpeg);
Image1.Visible=true;
Image1.ImageUrl=Server.MapPath(".")+@"\s_"+namestr;
}
}