Instagram lends itself to posting square photos. While you can post some slightly landsame/tall photos at 1080x1350 (.8) you can't get close to the native photo/sensor size of 7952x5304 or 3/2 format (.66) without it really looking odd on Instagram. I looked at what most professional and successful phtogs are posting and it looks to be 50-50 on posting square photos vs posting originally sized horizontal photos .

What is your opinion on this? and what size is better for IG posting