This is a simple way to synchronize a folder hierarchy full of photos, some of which are marked for publication, between a local disk and a photo sharing service.

Archived; see https://github.com/dubinsky/gphoto-sync.

Picasa Web Albums.

The first service to be supported was Zenfolio, but I do not have a Zenfolio account any longer (see this post for historical background).

One of the goals of the design was to make adding more services easy: service interfaces are general enough and at the same time allow quirks of specific services to be accommodated.