[waltergomez]

Que es TALUMNOSFOTO ?
Te dejo una modificacion para mejorar tu codigo.

Código Delphi [-]
procedure TFRegMatricula.bObtenerClick(Sender: TObject);
var
    Jpg: TJpegImage;
    Stream: TMemoryStream;
begin
      if OpenPictureDialog1.Execute then
      begin
        Jpg := TJpegImage.Create;
        Jpg.LoadFromFile(OpenPictureDialog1.FileName);
        Stream := TMemoryStream.Create;
        Jpg.SaveToStream(Stream);
        Stream.Position := 0;
        dm.TALUMNOSFOTO.LoadFromStream(Stream);
        jpg.Free;
        Stream.Free;
      end;
end;