Not sure what you're asking for, but I think you're trying to use shoot(), which is described here:
http://wiki.graal.us/shoot
You can change the projectile's image in the last parameter:
PHP Code:
//#CLIENTSIDE
function onWeaponFired()
{
temp.angle = getangle(vecx(player.dir), vecy(player.dir));
shoot(player.x, player.y, player.z, temp.angle, 0, 0, "arrow", "barrow0.png");
}
If arrow.gani is too complicated you can make your own single-frame gani.