Issues with 360 slides and images showing

Good afternoon all, 

I'm trying to create a normal 2D project that utilizes 360 slides at various intervals. The first ones I entered into the program worked without issue. Now when I add a photo, its there but blank (white screen). I can add hotspots but can't move them or edit them in anyway because they are also blank. Please help!!! Is there a limit on the number of slides that can be added?