Instagram : Sharing to Other Social Networks like facebook
You can only get a link to photos and videos that have been shared publicly. If an account is set to private, you won’t be able to get a link to any of their posts.
To get a link to a post:
Tap (iOS) or(Android) above the post.
Tap Copy Link.
To get a link to a post from the web:
Open your web browser.
Go to instagram.com/username. For example, if the username is “johnsmith,” type in instagram.com/johnsmith as the URL.
Click the post you want to save and copy the link at the top of your browser.