Previously, the only way to find out whether a photo of you was uploaded to Instagram was to scroll through the activity feed Likewise, and without the ability to share a photo someone uploaded of another person to your own followers’
To tag someone in a photo, click on the ‘Add People’ option after you take a photo. You will them be asked to tap anywhere on the photo you want to tag someone and then type their profile name. You then select the ID and the photo gets tagged. You can not just tag new photos but also existing ones by clicking on the options key in the bottom right of each photo. Of course, you can only tag photos you have clicked.
Photos that have a tag briefly show an icon in the bottom left corner of the screen when you see them. You can then tap once on the photo to see the tags. You can click on the tag to go to the profile of that person.
Unfortunately with this new addition if you want to add tags to your old photos, you’ll have to do it manually, one by one.