wx.getSetting({
            success(res) {
              if (!res.authSetting[‘scope.writePhotosAlbum‘]) {
                wx.authorize({
                  scope: ‘scope.writePhotosAlbum‘,
                  success() {
                    console.log(‘授权成功‘)
                  }
                })
              }
            }
          })

          var imgSrc = "http://wxserver.knowway.cn/uploadpic/xiangmu/zhongjinwenjuan/images/1/p1_bg.jpg"
          wx.downloadFile({
            url: imgSrc,
            success: function (res) {
              console.log(‘图片保存到本地‘);
              console.log(res);
              wx.saveImageToPhotosAlbum({
                filePath: res.tempFilePath,
                success: function (data) {
                  console.log(data);
                },
                fail: function (err) {
                  console.log(err);
                  if (err.errMsg === "saveImageToPhotosAlbum:fail auth deny") {
                    console.log("用户一开始拒绝了，我们想再次发起授权")
                    console.log(‘打开设置窗口‘)
                    wx.openSetting({
                      success(settingdata) {
                        console.log(settingdata)
                        if (settingdata.authSetting[‘scope.writePhotosAlbum‘]) {
                          console.log(‘获取权限成功，给出再次点击图片保存到相册的提示。‘)
                        } else {
                          console.log(‘获取权限失败，给出不给权限就无法正常使用的提示‘)
                        }
                      }
                    })
                  }
                }
              })
            }
          })