Did you look around using FileZilla for the files? Did you look in /DataVolume/ ?
You should also look at where your current version of Twonky is scanning for content
nano /etc/contentdir
or
vi /etc/contentdir
use this as a loose guide
By the way, you should really upgrade your Twonky to the latest version. In doing so, Twonky will definately rebuild its database.
If it turns out that the contents of the Shared Pictures directory are actually gone, you will have to do some data recovery. Pay someone, or do it yourself.
http://unix.stackexchange.com/questions/80270/unix-linux-undelete-recover-deleted-files
