I have the latest svn and its working, you know if you save it directly as seasonXX.tbn you have to set it to allfiles in filetype if not you will end up with seasonXX.tbn.jpg
also XX is the season # (season01.tbn , season02.tbn, ect...)
the method 2 is foolproof you just browse for the thumb and select it.
the thumbs goes in
with method 2 it doesnt matter where you save it as long as you can browse it from XBMC because its just browse and select XBMC will then create the .tbn file.
In method 1 you are creating the tbn file directly.
(remember to reload the season, from the Info view just select reload and No to reload all episodes .NFO)
(Info view -> from context menu in the desire show select TVshow information)