wxml:

<view>
    <image src="{{imgUrl}}" mode="aspectFit"/>
  <button bindtap="sel">选择图片</button>
  <button bindtap="upload">上传图片</button>
    <!-- <image src="https://7465-test-1adh8-1259161555.tcb.qcloud.la/images/1?sign=0fec6515dc17db97123585c0a0a46589&t=1556961798"/> -->
  <button bindtap="download">下载上传的图片</button>
  <button bindtap="getUrl">根据id换取图片路径</button>
    <image src="{{downImgUrl}}"/>
  <button bindtap="delFile">删除文件</button>
</view>

js:

data: {
    imgUrl:'../../images/bf.jpg',
    downImgUrl:'',
    fileId:''
},
onLoad: function() {
    this.db = wx.cloud.database();
    this.mycol = this.db.collection("022project");
},
//选择图片
sel(){
    var that = this;
    wx.chooseImage({//wx.chooseImage
        success(res){
            console.log("选择图片成功！",res)
            that.setData({
                imgUrl:res.tempFilePaths[0]
            })
        }
    })
},
//上传图片
upload(){
    var that = this;
    wx.showToast({
        title:"上传中",
        icon:"loading"
    })
    wx.cloud.uploadFile({
        cloudPath:"images/1",//可以不写后缀，会自动创建到云储存中
        filePath:that.data.imgUrl,
        success(res){
            wx.showToast({
                title:"上传成功",
                icon:"success",
                duration:2000
            })
            that.setData({
                fileId:res.fileID
            })
            console.log("图片上传成功！",res)
        }
    })
},
//下载上传的图片
download(){
    wx.cloud.downloadFile({
        fileID:this.data.fileId
    }).then(res=>{
        console.log("下载成功！",res)//
    })
},
//换取路径
getUrl(){
    var that = this;
    wx.cloud.getTempFileURL({
        //--fileList: 数组元素为需要换取文件路径的id值
        fileList:["cloud://test-1adh8.7465-test-1adh8/images/1"],
        success(res){
            console.log("获取真实路径",res)//返回的是图片下载地址
            that.setData({
                downImgUrl:res.fileList[0].tempFileURL
            })
        }
    })
},
//删除文件
delFile(){
    var that = this;
    wx.cloud.deleteFile({
        fileList:["cloud://test-1adh8.7465-test-1adh8/images/1"],
        success(res){
            console.log("删除文件：",res)
            that.setData({
                downImgUrl:res.fileList[0]//TODO
            })
        }
    })
}