I think Thumbnailer can be modified to be more effective. The high point of Filebrowser is that it is much easier to upload photos via ftp than using a web form, but thumbnailing is annoying because it is a huge manual process. It should be a one click process.
1. click 2. get all the files recursively 3. sort them in descending order by the most recent 4. check if it has thumbnail > if not generate and continue > else stop
Point 4 assumes that if it found a thumbnailed image, the rest will be thumbnailed, so there is no point in checking all files.