就像@AndreasRejbrand在评论中说的那样，可以使用数组，例如：

var
  Images: array[0..6] of TImage;
  TargetTop: Integer;
  ...

...

Images[0] := imgCourses7;
Images[1] := imgCourses6;
Images[2] := imgCourses5;
Images[3] := imgCourses4;
Images[4] := imgCourses3;
Images[5] := imgCourses2;
Images[6] := imgCourses1;

iCoursesCount := Length(Images);
TargetTop := 6+(41*iCoursesCount);

for I := 0 to iCoursesCount-1 do begin
  Images[I].Top := 6;
end;

for I := 0 to iCoursesCount-1 do
begin
  Dec(TargetTop, 41);
  while Images[I].Top <> TargetTop do
  begin
    Images[I].Top := Images[I].Top + 6;
    Sleep(8);
    Application.ProcessMessages;
    if Images[I].Top >= TargetTop then
    begin
      Images[I].Top := TargetTop;
      Break;
    end;
  end;
end;

也就是说，你真的不应该使用每次迭代都需要Application.ProcessMessages()的休眠循环。你可以考虑使用TTimer或TThread.ForceQueue()。不要不必要地阻塞主UI线程。例如：

published
  procedure FormCreate(Sender: TObject);
private
  Images: array[0..6] of TImage;
  TargetTop: Integer;
  CurrentImage: Integer;
  procedure StartAnimatingMenu;
  procedure StartAnimatingNextMenuItem;
  procedure StepAnimateCurrentMenuItem;
  ...

...

procedure TMyForm.FormCreate(Sender: TObject);
begin
  Images[0] := imgCourses7;
  Images[1] := imgCourses6;
  Images[2] := imgCourses5;
  Images[3] := imgCourses4;
  Images[4] := imgCourses3;
  Images[5] := imgCourses2;
  Images[6] := imgCourses1;
end;

procedure TMyForm.StartAnimatingMenu;
var
  I: Integer;
begin
  for I := Low(Images) to High(Images) do begin
    Images[I].Top := 6;
  end;
  TargetTop := 6+(41*Length(Images));
  CurrentImage := -1;
  StartAnimatingNextMenuItem;
end;

procedure TMyForm.StartAnimatingNextMenuItem;
begin
  Inc(CurrentImage);
  if CurrentImage < Length(Images) then
  begin
    Dec(TargetTop, 41);
    StepAnimateCurrentMenuItem;
  end;
end;

procedure TMyForm.StepAnimateCurrentMenuItem;
begin
  if Images[CurrentImage].Top <> TargetTop then
  begin
    Images[CurrentImage].Top := Images[CurrentImage].Top + 6;
    TThread.ForceQueue(nil, StepAnimateCurrentMenuItem, 8);
  end
  else if Images[CurrentImage].Top >= TargetTop then
  begin
    Images[CurrentImage].Top := TargetTop;
    StartAnimatingNextMenuItem;
  end;
end;