# fixing a submodule
$ git submodule update --remote --merge
I use the Hugo gallery theme
It broke on my britishbogroll gallery which I think is due to an update to sasl which resizes/processes images and an obsolete reference.
After a certain amount of faffing I re-pulled my repo and updated the git submodule - the theme which fixed it. As there are quite lot of pictures you sometimes have to be patient to alow Hugo to rebuild it which is probably how I broke it before.. See the invocation above!