Before you save, pick the shape of the picture and how large it should be.
Frame
4:5 · 1:1 · 9:16 · 3:2 · 16:9. The frame changes the shape of the picture around the rug, not the rug itself. The screen shows exactly what will be saved.
Size
1080, 2160 or 4320 pixels wide; the height follows the frame. Pictures use the size as chosen. Videos shrink the largest sizes until they fit the H.264 format: a 4320-wide 4:5 video comes out 2718 × 3400, and at 60 frames a second a few of the largest sizes cannot be made at all.