If you have noticed some of your images are not coming through when you open and close your fridge door, it could due to a poor WIFI signal at the time FridgeCam takes a picture. Once you have a stronger WIFI signal the image should come through. If not, try to open and close the fridge door to take a new picture.
You can check the WIFI signal strength by going to Features > Settings, where you can see the signal strength and RSSI which should be no higher than -60m anything above -60 will stop the image from being sent.
Another cause for missed images could be if you open and close the fridge door too quickly, this does not give the camera enough time to wake up and take the picture.