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Bootstrap-4 - Interview Questions
What is Bootstrap 4 Responsive images ?
Responsive images automatically adjust to fit the size of the screen. Bootstrap are made responsive with .img-fluid class to the  tag.  The .img-fluid class applies max-width: 100%; and height : auto; are applied to the image so that it scales with the parent element.

<img src="image.jpg" class="img-fluid" alt="responsive Image">