According to Instagram’s Co-founder Mike Krieger, they are improving the resolution of photo uploads from 640×640 to 1080×1080 starting today.
We're rolling out 1080×1080 uploads (and higher-quality viewing) for IG on iOS and Android. Let me know if feed looks a bit sharper today 🙂
— Mike Krieger (@mikeyk) July 6, 2015
Krieger also mentioned that a lot of work has been put into image optimization to minimize the affect on bandwidth.
We did a lot of work on image optimization so network bandwidth should not be affected
Have you noticed photos on Instagram looking sharper now? Comment below.