https://limmat-club.ch/clubdesk/webpage/fixes/captions.js

1function doAdjustCaptionContainer(image) {
2    var captionContainer = getNextSibling(image, ".cd-image-caption-container");
3    if (captionContainer == null) {
4        return;
5    }
6    setTimeout(function () {
7        if (image.naturalHeight / image.naturalWidth > image.height / image.width) {
8            var dw = (image.width - image.height * image.naturalWidth / image.naturalHeight) / 2;
9            captionContainer.style.cssText = 'left: ' + dw + 'px; right: ' + dw + 'px;';
10        }
11        if (image.naturalHeight / image.naturalWidth < image.height / image.width) {
12            var dh = (image.height - image.width * image.naturalHeight / image.naturalWidth) / 2;
13            captionContainer.style.cssText = 'top: ' + dh + 'px; bottom: ' + dh + 'px;';
14        }
15    }, 100)
16
17}
18
19var getNextSibling = function (elem, selector) {
20    var sibling = elem.nextElementSibling;
21    while (sibling) {
22        if (sibling.matches(selector)) {
23            return sibling;
24        }
25        sibling = sibling.nextElementSibling
26    }
27}
28
29function adjustCaptionContainer() {
30    document.querySelectorAll('.cd-image-contain').forEach(function (image) {
31            if (image.width > 0) {
32                doAdjustCaptionContainer(image);
33            } else {
34                image.addEventListener('load',
35                    function (e) {
36                        doAdjustCaptionContainer(image);
37                    });
38            }
39        }
40    )
41}