image responsive bootstrap code example

Example 1: bootstrap class align center image

class="mx-auto d-block"

Example 2: bootstrap image size

Width 25%
Width 50%
Width 75%
Width 100%

Example 3: image responsive bootstrap 4

 //This will make your image responsive

Example 4: bootstrap Image thumbnails

In addition to our border-radius utilities, you can use 
.img-thumbnail to give an image a rounded 1px border appearance.