How to fit an image inside a Bootstrap 3 div?

Question

I am using a div tag in code as shown below:

Answer 1

It is safe to assume that by fitting you mean covering all of the width. This is because

1. You typically do not know the height just by using col-sm-6 or col-md-6 or col-lg-4.
2. There is a huge probability of loss in aspect ratio of the image if you try to resize it according to your own will.

Use for fitting the column. This will fit your image width-wise into the column and will automatically modify the height (keeping the aspect ratio in mind), so you do not have to worry about image getting illogically resized.