P.S remember:
Check out:
I found this from @LiyahxWrites 's linktree 
If you want image resized to 1 panel, enter:
Width: 640
Height: 1136
If you want image resized to 2 panels, enter:
Width: 1280
Height: 1136
If you want image resized to 3 panels, enter:
Width: 1920
Height: 1136
(Don’t forget to choose an image and after you re-size it, you can re-size it again to take up diff panels, 1-3 panels, etc, and re-size other images and download them)