具体内容如下

Page({

 /**
  * 页面的初始数据
  */
 data: {
  pics: [],
  count: 9, //上传图片最大数量
  // showImgUrl: "", //路径拼接，一般上传返回的都是文件名，
  uploadImgUrl: 'https://xxx/UploadHandler.ashx', //图片的上传的路径
  detailPics: [], //上传的结果图片集合
 },
 selectimages() {
  var that = this;
  var detailPics = that.data.detailPics;
  if (detailPics.length >= that.data.count) {
   wx.showToast({
    title: '最多选择' + that.data.count + '张！',
   })
   return;
  }
  wx.chooseImage({
   count: that.data.count, // 最多可以选择的图片张数，默认9
   sizeType: ['original', 'compressed'], // original 原图，compressed 压缩图，默认二者都有
   sourceType: ['album', 'camera'], // album 从相册选图，camera 使用相机，默认二者都有
   success: function(res) {
    var imgs = res.tempFilePaths;
    for (var i = 0; i < imgs.length; i++) {
     that.data.pics.push(imgs[i])
    }
    that.setData({
     pics: that.data.pics
    })
    console.log(that.data.pics)
     that.uploadimg({
     url: that.data.uploadImgUrl, //这里是你图片上传的接口
     path: that.data.pics, //这里是选取的图片的地址数组
    });
   },
  })
 },
 //多张图片上传
 uploadimg: function(data) {
  wx.showLoading({
   title: '上传图片中...',
   mask: true,
  })
  var that = this,
   i = data.i ? data.i : 0,
   success = data.success ? data.success : 0,
   fail = data.fail ? data.fail : 0;
  wx.uploadFile({
   url: data.url,
   filePath: data.path[i],
   name: 'fileData',
   formData: null,
   success: (resp) => {
    wx.hideLoading();
    success++;
    var str = resp.data //返回的结果，可能不同项目结果不一样
    var pic = JSON.parse(str);
    var pic_name = pic.url;
    var detailPics = that.data.detailPics;
    detailPics.push(pic_name)
    that.setData({
     detailPics: detailPics
    })
   },
   fail: (res) => {
    fail++;
    console.log('fail:' + i + "fail:" + fail);
   },
   complete: () => {
    i++;
    if (i == data.path.length) { //当图片传完时，停止调用   
     that.send()
     console.log('执行完毕');
     console.log('成功：' + success + " 失败：" + fail);
     var myEventDetail = {
      picsList: that.data.detailPics
     } // detail对象，提供给事件监听函数
     var myEventOption = {} // 触发事件的选项
     that.triggerEvent('myevent', myEventDetail, myEventOption) //结果返回调用的页面
    } else { //若图片还没有传完，则继续调用函数
     data.i = i;
     data.success = success;
     data.fail = fail;
     that.uploadimg(data); //递归，回调自己
    }
   }
  });
 },
})

效果图：