Picasa: Sync to web – sometimes creates duplicate folders. A good summary of why Picasa sometimes duplicates folders in the web albums environment.
My plan is to import items into Picasa, edit, name, caption, etc and then click the sync to web button. This should be OK.
In the past, I have pressed the upload button while importing and then done some edits and then clicked sync to web. I think the latter is what was causing the duplication. We’ll see.