From Indie IT Wiki
View Full Size Photos
- Visit the Instagram website from any browser. Log in using your credentials if not done already.
- Now, go the profile of the user whose picture you want to see in full size. Click on the desired photo. Note: You won’t be able to click on a photo from the news feed. So, make sure you are on the profile page.
- After clicking on the photo, you need to append media/?size=l in the url and press ENTER.
e.g. https://www.instagram.com/p/B2sAvRLg8dY/ to https://www.instagram.com/p/B2sAvRLg8dY/media/?size=1
(Spot the Voyager fan at the front! :-)