Matlab - Imagenes y pop up menu

% --- Executes on selection change in popupmenu1.

function popupmenu1_Callback(hObject, eventdata, handles)

% hObject    handle to popupmenu1 (see GCBO)

% eventdata  reserved - to be defined in a future version of MATLAB

% handles    structure with handles and user data (see GUIDATA)

seleccion=get(hObject,'Value');

if seleccion==2

    cla;

    a=imread('foto1.png');

    imshow(a,'Parent',handles.imagen);

elseif seleccion==3

    cla;

    a=imread('foto2.png');

    imshow(a,'Parent',handles.imagen);

elseif seleccion==4

    cla;

    a=imread('foto3.png');

    imshow(a,'Parent',handles.imagen);

elseif seleccion==1

    cla;

    a=imread('imagenenblanco.png');

    imshow(a,'Parent',handles.imagen);

end