Fixed icon in scrollable div - css

Question

I know that fixed positioning does not work relative to the parent, only to the browser window and the solution is absolute, but I also have a problem with that.
In the div in which I need a scroll inside, I have to put the icon always visible in the bottom right corner.
My fiddle: https://jsfiddle.net/nck7o0jL/
Below is my code.
.big {
height: 600px;
width: 600px;
border: 2px solid black;
}
.small {
height: 300px;
width: 300px;
border: 2px solid red;
overflow: auto;
position: relative;
resize: both;
}
img {
width: 30px;
height: 30px;
position: absolute;
right: 15px;
bottom: 15px;
}
<div class="small"><img src="https://cdn4.iconfinder.com/data/icons/ionicons/512/icon-close-circled-128.png">
<div class="big">
</div>
</div>
As you can see, by stretching the div.small the icon is held, but during the scroll it is not.
Will someone give a helping hand?

Answer 1

You can approximate this using flexbox and position:sticky
* {
margin: 0;
padding: 0;
box-sizing: border-box;
}
.big {
height: 600px;
width: 600px;
flex-shrink: 0;
}
.small {
height: 300px;
width: 300px;
border: 2px solid red;
overflow: auto;
resize: both;
display: flex;
}
img {
width: 30px;
height: 30px;
margin: auto 0 15px auto;
position: sticky;
order: 1;
right: 15px;
top: calc(100% - 45px);
}
<div class="small"><img src="https://cdn4.iconfinder.com/data/icons/ionicons/512/icon-close-circled-128.png">
<div class="big">
</div>
</div>