Yahoo Messenger PhotoSharing folder

I am working on a case at the moment where I have hundreds of indecent images in the PhotoSharing folder of the Yahoo messenger cache directory. PhotoSharing has 45 subfolders which are named with 5 alphanumeric charaters, all starting with 'S'.

Does anyone know of a way to resolve those subfolders to a particular message session or user ID or whether the files in the folders are a cached copy of files transmitted by the local user?

Thanks )