The pictures will display individually without a slider in the control panel SETTING editor but should now be displaying properly in a slider on your booking page.
The default slider still works if it is displayed in a hidden element, for example "room more details" but some slider options may not work and the size of the containing div may need to be specified so the slider can render at the correct size when it opens. For example use something like <div class="flexslider" style="width:240px;height:180px"> to force a size.