cl_avatar_convert_png
cl_avatar_convert_png is a console command available in all 
Source games.
cl_avatar_convert_png is a console command that create PNG images from RBG files. It requires sv_cheats 1 to work.
Move RGB files into game ...<MOD>/avatars/ folder. Launch game with console enabled, in mainmenu, turn sv_cheats 1 and use command cl_avatar_convert_png
Game will create PNG pictures from all valid RGB files inside ...<MOD>/avatars/ folder.
Console also spew output message:
Converted rgb 'avatars/default.rgb'->'avatars/default.png'.
Note:Works (only in 
) ?