may I recommend irfanview with plugins to do jpeg lossless rotation :-)
I have IrfranView32 v2.18 for windows.
I think this version is too old to do what you mention. (01-06-97)
Is there a Linux version, or a version for the Zaurus?
EDIT: I got Infranview 3.98 from here: (free)
http://www.irfanview.com/For the lossless *.jpg plugin, download this:
iv_misc.zip (In the misc plugins)
Only thing is, this program is windows only and won't work/compile for the Z
It would be nice to do lossless rotation on the Z itself..