filename="pic.jpg"                           '原始图片
Set Jpeg1 = Server.CreateObject("Persits.Jpeg")
Jpeg1.Open Server.MapPath(filename)       
iWidth=Jpeg1.OriginalWidth            '图片的宽度
iHeight=Jpeg1.OriginalHeight            '图片的高度
iiwidth=204                                       '水印图片的宽度
iiheight=32                                       '水印图片的高度

'水印图居左上
jpeg1.Canvas.DrawPNG 5, 5,Server.MapPath("logo.png")

'水印图居右上
'jpeg1.Canvas.DrawPNG iWidth-iiWidth-5, 5, Server.MapPath("logo.png") 

'水印图居左下                      
'jpeg1.Canvas.DrawPNG 5, iHeight-iiHeight-5, Server.MapPath("logo.png")

'水印图居右下
'jpeg1.Canvas.DrawPNG iWidth-iiWidth-5, iHeight-iiHeight-5,Server.MapPath("logo.png")

'水印图居中
'jpeg1.Canvas.DrawPNG iWidth/2-iiWidth/2, iHeight/2-iiHeight/2, Server.MapPath("logo.png")

jpeg1.save Server.mappath(filename)         '保存打上水印的图片将覆盖原图,亦可另存
Set Jpeg1 = Nothing