I always found the small preview images in the files selection dialog annoying. With similar images, choosing the right one was often a matter of luck. I found a solution with a very simple CSS correction. But I wonder if this is the best solution, or if there is an “official” solution from the Kirby team?
/assets/css/custom-panel.css
.k-dialog-body .k-item[data-layout=list] {
--item-height: 4rem;
}