An update to Instagram brings the iOS share extensions so that you can post photos without ever opening Instagram itself. However, by doing this you lose the ability to use filters.
As long as you turn on the extension, any app that supports iOS’ official sharing method can send a photo Instagram’s way. In order to share a photo with Instagram when you are in a supported app, select and image, then tap on “share,” and choose Instagram from the share sheet.
The new feature is particularly big deal if you’re fond of third-party imaging apps, which don’t always automatically save pictures to your photo library.
The addition is overdue, to put it mildly. Android users have had this share-from-anywhere luxury for a while, and numerous other photo-focused apps, like Flickr, have had iOS sharing extensions for a long time.