By syncing contacts, the contacts in both accounts will be made to be identical. By moving contacts, each contact will be copied to the destination account and then deleted from the source account so as to retain only one copy of each contact.
By syncing/moving photos, your contact photos will be synced/moved between contact accounts.
Merge Contacts (2-way)
By merging contacts during 2-way syncs, the contents of matching contacts will be merged when necessary (for example, during the initial sync).
Merge Contacts (1-way)
By merging contacts during 1-way syncs/moves, the contents of matching contacts will be merged.
Auto Add to Group
By enabling this setting, when contacts are synced/moved, they will automatically added to the specified group.