限制上传图片大小和格式代码

        /// <summary>
        /// 限制上传图片大小和格式
        /// </summary>
        /// <param name="url">图片路径</param>
        /// <param name="width">图片宽度</param>
        /// <param name="heigth">图片高度</param>
        /// <param name="IsDel">是否删除图片</param>
        protected bool LimitImageSize(string url,int width,int heigth,bool IsDel)
        {
            FileStream stream = new FileStream(Server.MapPath("./" + url), FileMode.Open, FileAccess.Read);
            System.Drawing.Image tempimage = System.Drawing.Image.FromStream(stream, true);
            string[] format = url.Split('.');
            string fileext = format[3].ToString();
            if (fileext.Equals("jpg") || fileext.Equals("JPG"))
            {
                int imagewidth = tempimage.Width;
                int imageheight = tempimage.Height;
                if (width >= imagewidth && heigth >= imagewidth)
                {
                    stream.Close();
                    if (IsDel==true)
                    {
                        var ImageUrl = new FileInfo(Server.MapPath("./" + url));
                        ImageUrl.Delete();
                    }
                    Alert.ShowInTop("图片应大于或等于350*240px");
                    return true;
                }
                else
                {
                    stream.Close();
                    return false;
                }
            }
            else
            {
                stream.Close();
                if (IsDel == true)
                {
                    var ImageUrl = new FileInfo(Server.MapPath("./" + url));
                    ImageUrl.Delete();
                }
                Alert.ShowInTop("图片应为JPG格式");
                return true;
            }
        }