The image from my camera in the rule editor is too dark to see

When you are editing rules, you can click the arrows above the image to display images taken at earlier times. A current image from that camera is displayed on the right. Above it the text "Image From:" and a time range is displayed. This indicates an hour range from which the still image was taken. If the image from the current time is too dark to use, for example, you can click the arrows to the left of the time range to display an image from the previous hour. Keep going until you find an image that is suitable.