If you're looking to utilize bootstrap for your project, I would recommend making use of the built-in grid classes such as "container", "row", and "col-*".
For more information, check out: https://getbootstrap.com/docs/4.0/layout/grid/
To implement this in your markup, follow the structure below:
.sprite {
text-align: center;
position: relative;
}
.sprite-span-level {
position: absolute;
right: 5px;
}
.sprite-img {
width: 100%;
}
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" rel="stylesheet"/>
<div class="container">
<div class="row">
<div class="col-4">
<div class="sprite bg-info rounded p-1 m-1">
<span class="sprite-span-level">Top-right text over image</span>
<img class="sprite-img" src="http://www.politicalmetaphors.com/wp-content/uploads/2015/04/blog-shapes-square-windows.jpg">
<span class="sprite-span-nickname">Text under image</span>
</div>
</div>
<div class="col-4">
<div class="sprite bg-info rounded p-1 m-1">
<span class="sprite-span-level">Top-right text over image</span>
<img class="sprite-img" src="http://www.politicalmetaphors.com/wp-content/uploads/2015/04/blog-shapes-square-windows.jpg">
<span class="sprite-span-nickname">Text under image</span>
</div>
</div>
<div class="col-4">
<div class="sprite bg-info rounded p-1 m-1">
<span class="sprite-span-level">Top-right text over image</span>
<img class="sprite-img" src="http://www.politicalmetaphors.com/wp-content/uploads/2015/04/blog-shapes-square-windows.jpg">
<span class="sprite-span-nickname">Text under image</span>
</div>
</div>
<div class="col-4">
<div class="sprite bg-info rounded p-1 m-1">
<span class="sprite-span-level">Top-right text over image</span>
<img class="sprite-img" src="http://www.politicalmetaphors.com/wp-content/uploads/2015/04/blog-shapes-square-windows.jpg">
<span class="sprite-span-nickname">Text under image</span>
</div>
</div>
<div class="col-4">
<div class="sprite bg-info rounded p-1 m-1">
<span class="sprite-span-level">Top-right text over image</span>
<img class="sprite-img" src="http://www.politicalmetaphors.com/wp-content/uploads/2015/04/blog-shapes-square-windows.jpg">
<span class="sprite-span-nickname">Text under image</span>
</div>
</div>
<div class="col-4">
<div class="sprite bg-info rounded p-1 m-1">
<span class="sprite-span-level">Top-right text over image</span>
<img class="sprite-img" src="http://www.politicalmetaphors.com/wp-content/uploads/2015/04/blog-shapes-square-windows.jpg">
<span class="sprite-span-nickname">Text under image</span>
</div>
</div>
</div>
</div>