When working on MBS-13044 I realized adding class zoomable to the images on Release/Packaging broke the links for the wiki-hosted images. yvanzo helped figure out that the problem is the regex ensuring the image links are kept as wiki links rather than mb.org ones was originally assuming the wiki image prefix would be followed by /thumb, but that seems to be optional (possibly only for SVG?). We should fix the regex so that it works for all images.