Cay4redneck has brought up a good point to answer...
If they are "Blank" then you see the surrounding area just no game animals in it?
Or
Is the entire picture "Black"?

I've only gotten just a few "Blank" pic's out of hundreds taken by my camera. All of them were during the middle of the day with the camera pointing downward from about 12 ft high(I've tried 5 different angles so far)into an opening where the sunlight shined very brightly. It set off the sensor somehow with the combination of the sunlight and the movement of the canopy leaves but I'm not entirely sure why. It's a good camera for a feeding area and I have yet to get a "Whiteout" picture with it!