Problema cargando Imagen desde base de Datos

[[enecumene]]

Sigo con mi Odisea con este asunto lo que he hecho:

Función:

Código Delphi [-]
function CargarImagen(Campo:TBlobField): integer;
var
bS : TBlobStream;
buffer : Word;
hx : string;
begin
  Result := -1;
  bS := TBlobStream.Create(Campo, bmRead);
    try
      while (Result = -1) and
        (bS.Position + 1 < bS.Size) do
          begin
            bS.ReadBuffer(buffer, 1);
            hx := IntToHex(buffer, 2);
          if hx = 'FF' then begin
            bS.ReadBuffer(buffer, 1);
            hx := IntToHex(buffer, 2);
          if hx = 'D8' then Result := bS.Position - 2
            else if hx = 'FF' then
              bS.Position := bS.Position-1;
            end; //if
           end; //while
          finally
        bS.Free
      end; //try
end;

Aquí para cargar la imagen:

Código Delphi [-]
var
  bs: TBlobStream;
  Pic: TJPEGImage
begin
bS := TBlobStream.Create(ZTable1FOTO2, bmRead);
                try
                  bS.Seek(CargarImagen(ZTable1FOTO2),soFromBeginning);
                  Pic:=TJpegImage.Create;
                    try
                       Pic.LoadFromStream(bS);
                       Foto.Picture.Graphic := Pic;
                    finally
                       Pic.Free;
                    end;
                finally
                  bS.Free
                end;
end;

Resultado:

---------------------------
Debugger Exception Notification
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Project TimerPunch.exe raised exception class EInvalidCast with message 'Invalid class typecast'. Process stopped. Use Step or Run to continue.
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OK Help
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Me voy a tirar de la ventana!! .

Saludos.