I seem to be a bit late to the party, but I also have this problem. I have a Dell mini 10v running 10.10, which has an indicator LED next to the webcam to show when it is being used. this comes on when I open the program but when Photostory takes the picture (once the countdown has finished, that is) the LED goes off, then on again, then off, then finally on at which point it displays the photo which is either very dark or just very dark green. I assume that it is taking the picture in the middle bit of the webcam being on, but that this is not long enough for the webcam to 'warm up', hence it being very dark.
I seem to be a bit late to the party, but I also have this problem. I have a Dell mini 10v running 10.10, which has an indicator LED next to the webcam to show when it is being used. this comes on when I open the program but when Photostory takes the picture (once the countdown has finished, that is) the LED goes off, then on again, then off, then finally on at which point it displays the photo which is either very dark or just very dark green. I assume that it is taking the picture in the middle bit of the webcam being on, but that this is not long enough for the webcam to 'warm up', hence it being very dark.