function PhysicalResolveFileType(AStream: TStream): Integer;

var

 p: PChar;

begin

 Result := 0;

 if not Assigned(AStream) then

  Exit;

 GetMem(p, 10);

 try

  AStream.Position := 0;

  AStream.Read(p[0], 10);

  {bitmap format}

  if (p[0] = #66) and (p[1] = #77) then

  Result := 1;

  {tiff format}

  if ((p[0] = #73) and (p[1] = #73) and (p[2] = #42) and (p[3] = #0)) or

  ((p[0] = #77) and (p[1] = #77) and (p[2] = #42) and (p[3] = #0)) then

  Result := 2;

  {jpg format}

  if (p[6] = #74) and (p[7] = #70) and (p[8] = #73) and (p[9] = #70) then

  Result := 3;

  {png format}

  if (p[0] = #137) and (p[1] = #80) and (p[2] = #78) and (p[3] = #71) and

  (p[4] = #13) and (p[5] = #10) and (p[6] = #26) and (p[7] = #10) then

  Result := 4;

  {dcx format}

  if (p[0] = #177) and (p[1] = #104) and (p[2] = #222) and (p[3] = #58) then

  Result := 5;

  {pcx format}

  if p[0] = #10 then

  Result := 6;

  {emf format}

  if (p[0] = #215) and (p[1] = #205) and (p[2] = #198) and (p[3] = #154) then

  Result := 7;

  {emf format}

  if (p[0] = #1) and (p[1] = #0) and (p[2] = #0) and (p[3] = #0) then

  Result := 7;

 finally

  Freemem(p);

 end;

end;