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

 1<script language="VB" runat="server">   
 2Sub Page_Load(sender As Object, e As EventArgs) 
 3
 4Dim image,aNewImage As System.Drawing.Image   
 5dim width,height,newwidth,newheight as integer   
 6Dim callb As System.Drawing.Image.GetThumbnailImageAbort 
 7
 8'生成缩略图   
 9image=System.Drawing.Image.FromFile(Server.MapPath("classpic/"+"rs1.jpg"))   
10width=image.Width   
11height=image.height   
12if width>height then   
13newwidth=110   
14newheight=image.height/image.Width*newwidth   
15else   
16newheight=110   
17newwidth=image.Width/image.height*newheight   
18end if 
19
20aNewImage=image.GetThumbnailImage(newwidth,newheight,callb,new System.IntPtr())   
21aNewImage.Save(Server.MapPath("smallpic/"+"rs1.gif"))   
22image.Dispose() 
23
24End Sub   
25</script>