You can change the default photo that shows for the tour one of two ways as described below. The default photo shows on Manage Tours on the left, when the tour first loads and when you post it to Facebook or other places.  It also is included as the larger image in the Call2Action photo. 

FloorPlan Tours - the default photo is the first photo to show when the FloorPlan View loads.  To change it, go to Edit Photos on FloorPlans and at the bottom left, select the desired photo you want.  In this example, the first photo was removed, so the system went to the next photo in line, #2.  So photo 26 was ultimately selected.

Photo Tours - the default photo is the first one on the Edit Photos/Video page.  If you want a different one, make sure it is the first photo in the sequence (besides any intro type slides) and the Photo box is checked.

Note for YouTube - YouTube randomly selects the photo to be shown for videos…so unless you upload the photos to your own YouTube channel, this can’t be changed.