Bootstrap provides three classes that can be used to apply some simple styles to the images.
Adds border-radius:6px to give the image rounded corners
Makes the entire image round by adding border-radius:500px
Adds a bit of padding and a gray border
Responsive images automatically adjust to fit the size of the screen.
You can create responsive images by adding an .img-responsive class to the <img> tag. The .img-responsive class applies display: block; and max-width: 100%; and height: auto; to the image.