CSS How to make image size relative to parent?

Question

I want to place image in other image as you see below

And I made it using below codes.

HTML

  <div class="col col-span-1" style="position : relative">
      <div>
        <img style="max-width:800px; max-height:800px; 
                    width:100%; height:100%;" 
             src="https://i.imgur.com/iY3x1GC.png">
      </div>
      <div style="position : absolute; top: 80%; left:50%; ">
        <img src="https://i.imgur.com/C1uxk6Y.png" 
             style="width: 100%; height: 100%;">
      </div>
    </div>

CSS

.col-span-1 {
    flex-basis: 8.3333%;
}
.col {
    flex: 1 1 8%;
    margin: 0 0 0.5rem 0;
    padding: 0.5em 10px;
    box-sizing: border-box;
}

myJSFiddle

I made div1's image responsive with width using width : 100%

But I don't know how to make div2's image scale up/down relative to div1's image.

I want to make it like this.

->(responsive)

I want to use CSS only as possible, thanks in advance.

Answer 1

To resize small images, putting them in small container and pushing that small container with another element is a clean solution. In my opinion tables are great for that.

Here is the code;

<div class="col col-span-1" style="position : relative">
  <div>
    <img style="max-width:800px; max-height:800px;width:100%; height:100%;" src="https://i.imgur.com/iY3x1GC.png">
  </div>
  <table style="position: absolute;top: 75%;width: 85%;">
    <tbody>
      <tr>
        <td style=" width: 60%;"></td>
        <td style=" max-width: 90px; width: 39%;">
          <div style="">
            <img src="https://i.imgur.com/C1uxk6Y.png" style="width:100%; height: 100%;">
          </div>
        </td>
      </tr>
    </tbody>
  </table>    
</div>

Answer 2

here is the code

html:

<div id="container">
    <div id="main_image">   <img style="max-width:800px; max-height:800px; width:100%; height:100%;" src="https://i.imgur.com/iY3x1GC.png"></div>
    <div id="overlay_image"> <img src="https://i.imgur.com/C1uxk6Y.png" style="
    width: 100%;
    height: 100%;
"></div>
</div>

css:

#container{
    position: relative;
    width: 100%;
    height: 100%;
}
#main_image{
    width: 100%;
    height: 100%;

}
#overlay_image{
    position: absolute;
    bottom: 10px;
    right: 10px;
    width: auto;
    height: auto;

}
@media screen and (min-width: 601px) {
  #overlay_image{
    width:40px;
    }
}
@media screen and (max-width: 600px) {
  #overlay_image{
    width:20px;
    }
}