Instagram plus is the modded version of the official Instagram app. The Instagram plus app is developed by OGmods who also happens to be the developer of OGYouTube and OgBB. The modded apps comes with a whole lot of unique features which can't be found on the official app. One of them is the ability to zoom on pictures.

With Instagram Plus, you can zoom in on any pictures just by long clicking and then pinching to zoom in or out. You can also move around the photo by sliding your finger across the screen.Aside the ability to zoom in pictures you can also share direct links straight from the app, you can use more than one Instagram app on the same device simultaneously (OGInsta) and you can also download Instagram pictures and Video directly from the app without the help of any third party app.

Below are some of the Features Of Instagram Plus And OgInsta
=> Follow indicator (You'll see if someone is following you).
=> You can view profile pictures (Long click).
=> You can enlarge pictures (Long click).
=> Download any video or picture.
=> Auto start videos with or without sound.
=> Direct share URL
=> And many more features.

Download Links.
You can download both the Instagram and OgInsta from the link below.

Note: If you want to use more than one Instagram account/app on your phone then you have to download both the Instagram plus and OGInsta.

Source: http://www.yomitech.com/2016/09/download-instagram-pictures-and-videos.html