上传图片到服务器：

1.先在前端写一个选择图片的区域来触发wx.chooseImage接口并用wx.setStorage接口把图片路径存起来。

-wxml
  <view class="shangchuan" bindtap="choose">
    <image style="width:100%;height:100%;" src="{{tempFilePaths}}"></image>
  </view>

  <button formType='submit' class="fabu">发布项目</button>

  /**选择图片 */
  choose: function () {
    var that = this
    wx.chooseImage({
      count: 1,
      sizeType: ['original', 'compressed'], // 可以指定是原图还是压缩图，默认二者都有
      sourceType: ['album', 'camera'], // 可以指定来源是相册还是相机，默认二者都有
      success: function (res) {
        var tempFilePaths = res.tempFilePaths
        that.setData({
          tempFilePaths: res.tempFilePaths
        })
        console.log(res.tempFilePaths)

        wx.setStorage({ key: "card", data: tempFilePaths[0] })
      }
    })
  },

2.使用wx.uploadFile将刚才上传的图片上传到服务器上

  formSubmit2: function (e) {
        var that = this
        var card = wx.getStorageSync('card')
        wx.uploadFile({
          url: app.globalData.create_funds,
          filePath: card,

          name: 'card',
          formData: {
            'user_id': app.globalData.user_id,
            'person': e.detail.value.person,
            'company': e.detail.value.company,
          },
          success: function (res) {
            console.log(res)
          }
        })
      }
    }
  },