How to make images in the Flexslider the same height while maintaining proportions?

Question

css

Please tell me how to make the same height of images in Flexslider while maintaining proportions (height/
width ) because there are photos with faces (horizontal and vertical) and it turns out ugly.

Answer 1

use another slider, there is a slick for example.
There is a variableWidth property, this is what you need.

Answer 2

what about max-width: 100% ?