Question Placeholder Images

I would like to add this, but is it possible to get rid of the placeholder images so that they'll be hidden from members while the modification is worked on by myself? And if deleting the path to the placeholder image causes the real size of the potential ad to show, is there a way to keep that hidden too?

The placeholders will only show up after you've set up the ability to actually buy the ad space. So presuming you don't create prices for your ads, they won't show up