http://www.theverge.com/2015/7/6/8899807/instagram-1080p-pictures-photo-upload
The Verge recently made known the latest app versions of Instagram are uploading photos in 1080x1080 resolution. These photos can be easily sourced via HTML when browsing the site's source code. Can these be accessed via the official Instagram API? And if so, how?
[Update] After Mar 23, 2018
I used Ekrem Gurdal's answer to make it work:
The IG API gives you "link" attribute, e.g. https://www.instagram.com/p/BTduOwSAwN6/
Then you can append ?__a=1 to this e.g. https://www.instagram.com/p/BTduOwSAwN6/?__a=1
And you can extract from the json result where the high resolution photo is stored: graphsql.shortcode_media.display_url
Hope this helps. Maybe IG folks will also find a way to disable this in the future. Why do they not just include the hi-res photo in the API response, smh
[Update] As of Mar 23, 2018, workaround below doesn't work anymore.
Just to update anyone who's looking at this in 2018. The solution that worked for me is to remove the "vp/" on top of replacing the resolution to 1080x1080.
E.g.
https://scontent.cdninstagram.com/vp/41d5aee08758061976d26e48f45e673a/5ADA338E/t51.2885-15/s320x320/e35/20065394_1785212551507111_5192354829363576832_n.jpg
to
https://scontent.cdninstagram.com/41d5aee08758061976d26e48f45e673a/5ADA338E/t51.2885-15/s1080x1080/e35/20065394_1785212551507111_5192354829363576832_n.jpg