By setting the default prefix url to /images/ (instead of hardcoding it), the code now matches the documentation, which states
Finally the
image paths, by default assume there is a folder on the servers root path
called '/images', eg '/images/zoomin_rest.png'. If you need to adjust
these paths, prefer setting the option.prefixUrl rather than overriding
every image path directly through this setting.
By setting the default prefix url to /images/ (instead of hardcoding it), the code now matches the documentation, which states