PictureSync primarily provides one-way synchronisation of data between applications:

Updating

Upload with synchronisation will be useful for you if your workflow has several steps, i.e. you import all your latest photos and then upload immediately (beacuse you don't have time to annotate there and then). When you do edit your annotations you can simple upload again and PictureSync will know to update instead of uploading afresh.

PictureSync is set to update by default when you try re-uploading a previously uploaded picture (shown as 'Online' in the list). You can turn this feature off in the preferences and all previously uploaded items will be ignored unless you reset them them for re-upload (see FAQ).

Services

Currently updating is available with Flickr, 23, Smugmug and VOX. More advanced functions are planned, including bi-directional synchronisation on your computer with iPhoto, and ultimately, between two accounts.

See the service-specific documentation for details of what features, annotations and settings are supported with synchronisation.

Requirements

If a picture is not listed as 'Online' it cannot be updated and will be uploaded as a new item.

Synchronisation requires that you have not disabled the 'remember status' preference, and requires OS X 10.4 for online states to be permanently saved between imports. Note that this is not currently possible with images imported from Aperture.

You may move and rename files and the status (the online ID of an uploaded item) will continue to be remembered, but note that Retrospect and possibly other backup solutions do not preserve the states. You can see the services and online IDs for an uploaded item in the information drawer, either in Services, or Attributes under 'Extended Attributes'.