Hugo only auto-shares page-bundle resources across translations when
each language has its own content directory; with filename-based
translation (index.fr.md / index.en.md in the same folder) a resource
with no language code is assigned to the default language only. Add
.en.-suffixed copies of every image referenced from English pages and
point the English markdown at them.
Configure Hugo multilingual mode (fr default, en secondary) with
Hextra's language-switch menu entry, and translate all existing
content pages to English using Hugo's per-file language suffix
convention (.en.md alongside .fr.md).
