前台页面：WebForm1.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server"> <title>无标题页</title> </head> <body> <form id="Form1" method="post" encType="multipart/form-data" runat="server"> <FONT face="宋体"> <TABLE id="Table1" style="Z-INDEX: 101; LEFT: 32px; WIDTH: 568px; POSITION: absolute; TOP: 24px; HEIGHT: 336px" cellSpacing="1" cellPadding="1" width="568" border="1"> <TR> <TD style="HEIGHT: 16px"><asp:label id="Label1" runat="server">要上传的图片</asp:label></TD> <TD style="HEIGHT: 16px"><INPUT id="upImage" type="file" name="File1" runat="server"></TD> <TD style="HEIGHT: 16px"><asp:button id="btnUp" runat="server" Text="上传并生成缩略图"></asp:button></TD> </TR> <TR> <TD style="HEIGHT: 154px"><asp:label id="Label2" runat="server">原图片</asp:label></TD> <TD style="HEIGHT: 154px" align="center" colSpan="2"><asp:image id="imageSource" runat="server"></asp:image></TD> </TR> <TR> <TD><asp:label id="Label3" runat="server">缩略图</asp:label></TD> <TD align="center" colSpan="2"><asp:image id="imageSmall" runat="server"></asp:image></TD> </TR> </TABLE> </FONT> </form> </body> </html> 后台代码：WebForm1.aspx.cs using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.HtmlControls; namespace WebApplication1 { public partial class WebForm1 : System.Web.UI.Page { //定义image类的对象 System.Drawing.Image image, newimage; //图片路径 protected string imagePath; //图片类型 protected string imageType; //图片名称 protected string imageName; //提供一个回调方法,用于确定Image对象在执行生成缩略图操作时何时提前取消执行 //如果此方法确定 GetThumbnailImage 方法应提前停止执行，则返回 true；否则返回 false System.Drawing.Image.GetThumbnailImageAbort callb = null; private void Page_Load(object sender, System.EventArgs e) { this.btnUp.Click += new System.EventHandler(this.btnUp_Click); this.Load += new System.EventHandler(this.Page_Load); // 在此处放置用户代码以初始化页面 } private void btnUp_Click(object sender, System.EventArgs e) { string mPath; if ("" != upImage.PostedFile.FileName) { imagePath = upImage.PostedFile.FileName; //取得图片类型 imageType = imagePath.Substring(imagePath.LastIndexOf(".") + 1); //取得图片名称 imageName = imagePath.Substring(imagePath.LastIndexOf("\\") + 1); //判断是否是JPG或者GIF图片,这里只是举个例子,并不一定必须是这两种图片 if ("jpg" != imageType && "gif" != imageType) { Response.Write("<script language='javascript'> alert('对不起！请您选择jpg或者gif格式的图片！');</script>"); return; } else { try { //建立虚拟路径 mPath = Server.MapPath("upFile"); //保存到虚拟路径 upImage.PostedFile.SaveAs(mPath + "\\" + imageName); //显示原图 imageSource.ImageUrl = "upFile/" + imageName; //为上传的图片建立引用 image = System.Drawing.Image.FromFile(mPath + "\\" + imageName); //生成缩略图 newimage = image.GetThumbnailImage(100, 100, callb, new System.IntPtr()); //把缩略图保存到指定的虚拟路径 newimage.Save(Server.MapPath("upFile") + "\\small" + imageName); //释放image对象占用的资源 image.Dispose(); //释放newimage对象的资源 newimage.Dispose(); //显示缩略图 imageSmall.ImageUrl = "upFile/" + "small" + imageName; Response.Write("上传成功!"); } catch { Response.Write("上传成功!"); } } } } } }