Ok, in the absence of further information I've gone ahead and moved my picture gallery folder into the public_html. Tiki is telling me that it is a security risk, but the files and folders have the same permissions as anything else in there, so I don't know if that is true.
Aside from that, it took me a while to figure out how to get batch uploading to work, except that it is moving all of my picture files on my server into the root picture directory, out of their respective subdirectories. Probably a long shot, but is there any way to get it to stop doing that, and leave the files where they are? I've looked through all the options on both the Batch upload page and the file gallery settings page and found nothing that would seem to do that.