Noise (grains in graphics) other than random

[WojTec]

This is standard random mono noise generator for images:

Delphi-Quellcode:

for J := 0 to ASource.Height - 1 do
begin
  for I := 0 to ASource.Width - 1 do
  begin
    Amount := Random(AFactor) - (AFactor shr 1);

    Bits.R := IntToByte(Bits.R + Amount);
    Bits.G := IntToByte(Bits.G + Amount);
    Bits.B := IntToByte(Bits.B + Amount);
  end;
end;

In PSP I see 2 other methods called uniform and gaussian. Do you know how it working? And maybe do you know another color/mono noise?