From today, you can finally zoom in on photos in Instagram!
It's very strange that this service, which is all about sharing photos, has never had the functionality which would allow people to check out the details in snaps. Partly that was because the resolution was so low that zooming in would make things look awful, but Instagram increased the pixels a while ago.
On iOS you can just pinch like so- cute doggies are not guaranteed.
This feautre is iOS only right now but will be coming to Android soon enough.