white color become transparent

["andry.tan" <andry.tan@xxxxxxxxx>]

hi.. everyone,

is anyone know how to make white color become transparent in very
smooth way? like in http://www.zazzle.com/cr/design/pt-shirt?

can php do that?

if you notice that the white color become transparent, it really
smooth can not just be made with imagecolortransparent function.

Any body know how to do it?

thank before friends...