小程序view选中后取消选择样式怎么变回去？

 <view class="bt1">
    <image src="{{back}}" class="bt1img" bindtap="ddjc" ></image>
    </view>

Page({
  data: {
    back:"/image/ddjc.png"
  },
  ddjc: function () {
    let that = this;
    that.setData({ 
    back: "/image/ddjc_selected.png"
    })
  }
})

上面是选中后的状态，下面是未选中，由于我用的是图片，取消选中图片还是不会还原，求助

增加一个checked字段来判断选中状态。当然也可以直接通过当前src判断，但是代码观赏性就太差了

Page({
  data: {
    back:"/image/ddjc.png"，
    checked:false
  },
  ddjc: function () {
    let that = this;
    if(that.data.checked==false){
        that.setData({ 
            back: "/image/ddjc_selected.png",
            checked: true
        })
    }else{
        that.setData({ 
            back: "/image/ddjc.png",
            checked: false
        })
    }
  }
})

//wxml
<view class="bt1">
    <image src="{{checked1?'/image/ddjc.png':'/image/ddjc_selected.png'}}" class="bt1img" bindtap="ddjc1" ></image>
    <image src="{{checked2?'/image/ddjc.png':'/image/ddjc_selected.png'}}" class="bt1img" bindtap="ddjc2" ></image>
</view>

//js
Page({
  data: {
    checked1:false,
    checked2:false,
  },
  ddjc1: function () {
    let that = this;
    that.setData({ 
        checked1: !that.data.checked1
    })
  },
  ddjc2: function () {
    let that = this;
    that.setData({ 
        checked2: !that.data.checked2
    })
  },
})

这是多个按钮的场景，src直接写在wxml里，这样再看js代码就很清晰了