O'Reilly logo
  • yuchen zhan thinks this is interesting:

In short, using the flex property to set the flex items’ sizes in conjunction with the one fixed size you care about – the width of the .detail-image – is the way to go.

From

Cover of Front-End Web Development: The Big Nerd Ranch Guide

Note

There's no need to set height but width for flex item, flexbox will calculate the height by the width being set.