i think you should add <div class="image-conatiner"></div>
to have more control on images in your model don’t leave them without any element to control them. check the code below
.Card_Badge {
box-sizing: border-box;
max-height: 350px;
overflow: hidden;
}
.image-container{
display:flex;
}
<div class="Card_Badge">
<div class="image-container">
<img alt="Badge Background" src="https://via.placeholder.com/100" style="max-width: 100px;max-height: 146px;display: flex;z-index: 1;">
<img alt="Secured Card" src="https://via.placeholder.com/100" ">
</div>
</div>