asp.net生成缩略图

　　当我们要上传图片的时候，往往需要生成缩略图，以往我们要使用第三方控件才能完成。在asp.net中用下面方法轻松搞定
<script language="VB" runat="server">
Sub Page_Load(sender As Object, e As EventArgs)

Dim image,aNewImage As System.Drawing.Image
dim width,height,newwidth,newheight as integer
Dim callb As System.Drawing.Image.GetThumbnailImageAbort

'生成缩略图
image=System.Drawing.Image.FromFile(Server.MapPath("classpic/"+"rs1.jpg"))
width=image.Width
height=image.height
if width>height then
newwidth=110
newheight=image.height/image.Width*newwidth
else
newheight=110
newwidth=image.Width/image.height*newheight
end if

aNewImage=image.GetThumbnailImage(newwidth,newheight,callb,new System.IntPtr())
aNewImage.Save(Server.MapPath("smallpic/"+"rs1.gif"))
image.Dispose()

End Sub
</script>