Set a width on the image:
<img class="card-img-top" src="~/Images/folders/folder-icon.png" style="width:32px;">
Or set a max-width on the image:
<img class="card-img-top" src="~/Images/folders/folder-icon.png" style="max-width:32px;">
Or use the grid layout utilities:
<div class="row">
<div class="col-sm">
<a href="@Url.Action("Modules","Home")" class="card-link">Me</a>
</div>
<div class="col-sm-1">
<img class="card-img-top" src="~/Images/folders/folder-icon.png">
</div>
</div>