It's moon

I recently created an APNG (you can check / download it over here) that was supposed to have 329 frames, but some of them were 1:1 repetitions cause nothing really moved and I believe it ended up having 261 frames only. Does the tool automatically remove duplicated frames or frames that are 1:1? Or did something go wrong? If the tool automatically does that, I think it's really neat and smart! ^^