how to attach picture to another picture?

Question

I want to do synchronising device, it measures phase shift between phases. It's a measurement device, that have a pointer like a clock.

It consists of two images, a frame and arrow, that rotates. but when i try to resize window i have the following:

My html:

<div>

    <div>
      <div className={classes.sync_point}> . </div>
      <img src={arpng} ref={point} alt="arrow" className={classes.arrow} />
      <img src={syncFrame} alt="syncframe" className={classes.syncFrame} />
    </div>

    <div className={classes.btn}> 
     <Button variant='contained' onClick={calculateResult}>SYNCHRONISE</Button>
    </div>

    <div>
      <h1>{word}</h1>
    </div> 

</div>

My css:

.syncFrame{
    margin-top: 40px;
    width: 50%;
    height: 50%;
    position: absolute;
    left: 20vh;
    z-index: 1;
}

.arrow{
    margin-top: 40px;
    width: 50%;
    height: 50%;
    position: relative;
    z-index: 2;
}

How can i bound that images so that when i resize the window or change my device it proportionaly resizes.

Answer 1

<div className="parent">
    <div className={classes.sync_point}>
        .
    </div>
    <img src={arpng} ref={point} alt="arrow" className={classes.arrow} />
    <img src={syncFrame} alt="syncframe" className={classes.syncFrame} />
</div>


.parent{ 
   height: ....;
   width: ....;
   border: 1px solid black;
   position: relative;
}
img, .sync_point {
   position: absolute;
   top: 50%;
   left: 50%;
   transform: translate(-50%, -50%);
   width: 100%;
   max-height: 100%;
}

Answer 2

You can use a container width position:relative and set the second image with position:absolute. You can set the pointer as you need with top:0, left:50%, bottom:0 and margin:auto

.container{
  background-color:blue;
  width: 50%;
  position: relative;
}
.clock{
  width:100%;
}
.pointer{
  position:absolute;
  top: 0;
  left: 50%;
  bottom: 0;
  margin: auto; 
  width: 40%;
  transform: rotate(-180deg);
  transition-duration: 1s;
  transform-origin: left;
}
.container:hover .pointer{
  transform: rotate(-45deg);
}

<div class="container">
    <img class="clock" src="https://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Circle_-_black_simple.svg/500px-Circle_-_black_simple.svg.png" alt="">
    <img class="pointer" src="https://upload.wikimedia.org/wikipedia/commons/thumb/8/8d/U%2B2192.svg/250px-U%2B2192.svg.png" alt="">
</div>