Masking Color

Ok so I want to make a walking animation with pictures because im making a 2D game.

1-Is that possible.
2-Is there a masking color AKA a see through color...you know with no opacity.....Hope you understand that I cant say it in the right words >.<

1. yes

2. whatever colour you designate

eg
LoadAnimImage("test.bmp") ; just an example name, whatever you have called the file, extension could be bitmap png etc
MaskImage test, 255, 255, 255 ; then use maskimage to set a mask colour (pure white here) rgb colours, check out help.

Thanks man.