I've seen some posts that mention image size, but none of them were really asking "what is it and why do I need the two options?" So I'm doing that now. In the main menu of the DJI Fly app under the Camera tab there's an image size option with the two choices of 4:3 or 16:9. I don't know what those mean. I'm new(ish) to both photography and droning alike so the major difference I see is the smaller picture on my phone screen when recording. Surely that isn't the only difference however because why on Earth would it be? So what are the differences, and what are the advantages/disadvantages to both?