Could you try to manually edit the
/usr/share/photoflow/themes/photoflow-dark.gtkrc
and un-comment the
font_name =
line in the file, as in the screenshot below? You can then adjust the font size to your liking… Meanwhile I will look for a better solution
Concerning the appimage, there is some library that is pulling in the system-wide pangocairo instead of the bundled one… I will try to investigate more deeply during the next days, if time allows.
Thanks!