If I like then unlike a photo, will the user who posted the photo know?
This is a follow-up to my Instagram Privacy Tips and FAQ post, which received many excellent questions. The answer to this like/unlike mystery is worthy of its own post because it deals with the concepts of push (notification outside of the app) versus pull (user activity/refreshes within the app).
First, understand this: iPhone apps that you open then leave to use another app are still running in the background. To fully close an iPhone app, on the home screen, double click the home button. Across the bottom, you’ll see the apps that are running. Press on any app icon for two seconds. They will start floating. Click the red minus circle to fully close each app. (Do this often: it saves memory and battery. Only run what you need.)
Can the other user tell I liked their photo if I unlike it afterward?
Recipient has push notifications on (regardless of IG app running or not): like notification received
Recipient has push notifications off and IG app actively in use: like notification received
Recipient has push notifications off and IG app open but not actively in use: like notification not received
Recipient has push notifications off and IG app not open: like notification not received
Why: Some users have Instagram notifications turned on so that they get alerts or banners on their iPhone home screen when actions are taken on IG, such as users liking their photos or leaving comments. (Adjust this in iPhone Settings -> Notifications -> Instagram -> choose Alerts, Banners, or None.)
The other user seeing your like is first dependent on if notifications (push) are turned on regardless of whether the IG app is open or not. If the user does not have notifications enabled and happens to refresh News between your like/unlike, your action will show there.
It’s not how quickly you unlike after a like, but how soon the recipient actively checks the app. If you like then unlike an hour later with no activity on the recipient side (the one who posted the picture) during the hour, then no notification will be received (unless push notifications are on).
With the IG app closed, the news feed is not updated until you launch the app. So using your intuition, squeeze in your unlike while your frenemy has IG closed or is on a plane.
If the IG app is open and actively being used, the like/heart icon appears above the News briefly but goes away (see left- the 1 would appear next to the heart). Immediately unliking won’t change this.
If notifications are turned off and the like/unlike recipient does not have IG actively running (i.e., in the background), then the recipient will not notice nor receive notification. If notifications are on, all bets are off: they may see the like.