Code for upload iamges:

chooseImage: choose the images to upload

previewImage: preview the image and enable slide 

chooseImage() {    wx.chooseImage({      count: 3,      sizeType: ['compressed'],      sourceType: ['album', 'camera'],      success: res => {        let currentImages = res.tempFilePaths        this.setData({          images: currentImages        })      },    })      },  previewImg(event) {    let target = event.currentTarget    let src = target.dataset.src        wx.previewImage({      current: src,      urls: this.data.images    })  },

 

Upload to the server:

uploadImage(cb) {    let commentImages = this.data.commentImages    let images = []    if (commentImages.length) {      let length = commentImages.length      for (let i = 0; i < length; i++) {        wx.uploadFile({          url: config.service.uploadUrl,          filePath: commentImages[i],          name: 'file',          success: res => {            let data = JSON.parse(res.data)            length--            if (!data.code) {              images.push(data.data.imgUrl)            }            if (length <= 0) {              cb && cb(images)            }          },          fail: () => {            length--          }        })      }    } else {      cb && cb(images)    }  },  onInput(event) {    this.setData({      commentValue: event.detail.value.trim()    })  },  chooseImage() {    let currentImages = this.data.commentImages    wx.chooseImage({      count: 3,      sizeType: ['compressed'],      sourceType: ['album', 'camera'],      success: res => {        currentImages = currentImages.concat(res.tempFilePaths)        let end = currentImages.length        let begin = Math.max(end - 3, 0) // latest three pictures        currentImages = currentImages.slice(begin, end)        this.setData({          commentImages: currentImages        })      },    })  },