Автор: http://www.swissdelphicenter.ch

function BitmapToRTF(pict: TBitmap): string;
var
  bi, bb, rtf: string;
  bis, bbs: Cardinal;
  achar: ShortString;
  hexpict: string;
  I: Integer;
begin
  GetDIBSizes(pict.Handle, bis, bbs);
  SetLength(bi, bis);
  SetLength(bb, bbs);
  GetDIB(pict.Handle, pict.Palette, PChar(bi)^, PChar(bb)^);
  rtf := '{\rtf1 {\pict\dibitmap0 ';
  SetLength(hexpict, (Length(bb) + Length(bi)) * 2);
  I := 2;
  for bis := 1 to Length(bi) do
  begin
    achar := IntToHex(Integer(bi[bis]), 2);
    hexpict[I - 1] := achar[1];
    hexpict[I] := achar[2];
    Inc(I, 2);
  end;
  for bbs := 1 to Length(bb) do
  begin
    achar := IntToHex(Integer(bb[bbs]), 2);
    hexpict[I - 1] := achar[1];
    hexpict[I] := achar[2];
    Inc(I, 2);
  end;
  rtf := rtf + hexpict + ' }}';
  Result := rtf;
end;