Thanks for your suggestions.
Using transform in css seems to work. I added this to the css file to make square thumbnails in the eventslist.
Code:
.jem-list-img {
position: relative;
width: 100px;
border: 0;
overflow: hidden;
height: 100px;
}
.jem-list-img img {
-moz-transform: translate(-50%, -50%);
-webkit-transform: translate(-50%, -50%);
-ms-transform: translate(-50%, -50%);
transform: translate(-50%, -50%);
position: absolute;
top: 50%;
left: 50%;
width: auto
}
I got the idea from here:
stackoverflow.com/questions/25261198/css-cropping-landscape-to-square
An even easier option would simply be
object-fit: cover;
However, it's not supported by older browsers.
