For some reason the Network Manager icon showed I had no network connection until at some point yesterday the network really stopped working. So in the Network Manager I created a wired connection and not only did that bring back my network, it also made f-spot work! Can’t see what the network has to do with f-spot, but I’m happy anyway.
For some other vague reason (I did not install or update anything of that kind) the “Unable to load NLS codepage cp437” error messages went away. The cifs-mounts are still mounted the same way. *puzzled*