Example using Twitter Bootstrap and flexbox and a few others. After seeing the number of incomplete answers to questions about flexbox css and bootstrap on stackoverflow I decided to make a quick example of how to accomplish this.
Flexbox works on all devices except for IE <= 9
Bootstrap 4 will be coming out soon which is suppose to have support for this kind of stuff by default with their cards and new grid. There is also a pretty cool bootstrap grid replacement out currently that works with bootstrap 3.
This example is using the current Bootstrap 3.0 thumbnails
I plan on dropping this template in the Bootstrap Genesis for Wordpress plugin to use for blog grid posts.