Both of the pictures you attached have been modified and possibly cropped.
The island is 1500x971, the other is 1242x883. None of the phantom options are for that low of a resolution so these have been resized. The island picture is a 3:2 ratio though, so they probably had it on the Medium setting in the app or they cropped from Large. Your picture is a 1.406 ratio, if you were using the DJI large setting it should be 4:3 or 1.333, so I'm not sure what happened there. In any case use small if you want it widescreen by default, all of the options have the same number of pixels wide, they are just cropped vertically.
FYI
Large: 4384x3288 - 4:3 - 14.4MP
Medium: 4384x2922 - 3:2 - 12.8MP
Small: 4384x2466 - 16:9 - 10.8MP