In the admin area under About Franz Josef -> Size and Dimensions it states that the Featured Image size is 850px wide and 450px high.
When uploading a featured image there are two sizes made that are being used for posts in rows, 300×159 and 600×300. The 300×159 version has the correct aspect ratio. The 600×300 version however, does not.
Compared to the featured image size, the correct size should be 600×318.
This results in pictures being cut off.
It can be seen when using a posts row with 2 or 3 columns which uses 600×300.