Ako urobiť hraničný polomer štvorcový bootstrap

bootstrap s polomerom ohraničenia

Border-radius
Add classes to an element to easily round its corners.

<img src="..." alt="..." class="rounded">
<img src="..." alt="..." class="rounded-top">
<img src="..." alt="..." class="rounded-right">
<img src="..." alt="..." class="rounded-bottom">
<img src="..." alt="..." class="rounded-left">
<img src="..." alt="..." class="rounded-circle">
<img src="..." alt="..." class="rounded-0">