my first skin need help !!

if i converd my TGA into a BLP i can see nothing ?

programs i use
w3 viewer
MGI PhotoSuite 8.1

what i have done bevore : load mdx from demonhunter take the demonhunter texture and converd it into TGA
i opent it with PhotoSuite and paint on it.
when im ready i converd it as BLP with w3 viewer
but if i open my BLP i see nothing ! ??
the only way too see it is if i save my TGA as BMP then converd it as BLP
but then i have an other problem : what is an alfa channel and how can i remove
the black corners from his weapon ! ?

blp is blizzards texture file, you cant see it, but you can see it ingame.
i dont know how you edit alpha channels with photosuite srry.

Problem solved
i have downloaded gimp
now my skin works