Q:

How to display image on the right side of div without ruining flex layout?

How can I insert an image on the right hand side of my div box without ruining my flex layout for the rest of the elements in the div. Here is a reference picture: 
I want to display an image on the right hand side where there is an empty place (the white) but am unsure on how to do this.
HTML
<div class="main-content">
        <div class="main-box">
          <div class="kills-container">
            <h1>5600</h1>
          </div>
          <div class="label-container">
            <p>Kills</p>
          </div>
        </div>
      </div>

CSS
.main-box {
  display: flex;
  flex-direction: column;
  box-sizing: border-box;
  background-color: white;
  height: 120px;
  width: 23%;
  box-shadow: 0 2px 4px 0 rgba(0,0,0,0.1);
}

.kills-container {
  display: flex;
  flex: 1;
  justify-content: flex-end;
  background-color: red;
  width: 50%;
}

.kills-container h1 {
  margin: 0;
  position: relative;
  right: 10%;
  align-self: flex-end;
  font-weight: normal;
}

.label-container {
  display: flex;
  flex: 1;
  justify-content: flex-end;
  width: 50%;
  background-color: green;
}

.label-container p {
  margin: 0;
  position: relative;
  right: 12%;
  top: 20%;
  align-self: flex-start;
  font-weight: lighter;
}

Thank you! :)

A:

You want to have two divs inside main-box, one for each side, and then position them using flex-row for the main-box.
HTML
<div class="main-content">
    <div class="main-box">
        <div class="left-side">
            <div class="kills-container">
                <h1>5600</h1>
            </div>
            <div class="label-container">
                <p>Kills</p>
            </div>
        <div class="right-side">
            <img src="yourimage"
        </div>
    </div>
</div>

CSS
.main-box {
  display: flex;
  flex-direction: row;
  box-sizing: border-box;
  background-color: white;
  height: 120px;
  width: 23%;
  box-shadow: 0 2px 4px 0 rgba(0,0,0,0.1);
}

.left-side {
    display: flex;
    flex-direction: column;
}

right-sire {
    display: flex;
    flex-direction: column;
}

