Wallpapers from Photoshop bad?

i make grahpics with photoshop cs2 and some of the ones that i make is pretty good so i decided to set it up as my wallpaper but when i save it as a jpg file i set the quality to 12 (max) but in jpg form it looks terrible then in the photoshop format. anyone kno what to change so the jpg file looks same as the photoshop file? or should i change it to TIFF or something

:withstupi