You have to download an application named as Instwogram created in order to use multiple Instagram account. You cannot find that app in Play Store because it is against Instagram TOS. 

Instwogram is an clone of Instagram created by Me-Nex S at XDA forum. You can do all the things which you are doing with your orignal Instagram app and you can also download pics and videos (download avaiable for root users only). There are two versions available of Instwogram one is stable (6.1.0) with no issues and the second one is beta version(6.4.1).

Download Stable Version

Download Newer Version

As i have read this on forum some people cannot link their Facebook profile to Instwogram. you can sort out this problem by applying the solution given below.

» First of all install official Facebook app on your Android device.

» Now login to your account and Navigate to Account Settings » Apps » Instagram » Remove Instagram.

» Now Open Instwogram not Instagram login to it and share any pic on it. 

» Now you can sucessfully link to your facebook account.

Now we can reply to our friends who was asking us 

Can we use multiple accounts in Instagram ??

Can I use two instagram accounts in my phone ??

To download pics and videos from Instwogram you have to Install Xposed framework module named as Instwogram downloader. To install Xposed framework you must have root access on your device. 

» First of all Install Xposed Installer.

» Now download Instwogram downloader module for version 6.4.1.

» Now Install the APK file and open Xposed Installer , tick Instwogram downloader in modules.

»  To activate module restart the device.

» Please Share this awesome trick with your friends on Facebook. Twitter. Google plus. Pinterest. Stumbleupon.

You might have seen Multi-window view in Samsung Mobiles like in Note 3 , Note 2 , Galaxy S4  or if you have ever used Omni rom before then you do not have any doubts about Multi window view. In other words Multi window is a concept in which you can open two apps together on same screen. If you still have doubt look at the image below

1. Your Android phone should be Rooted.

HOW TO INSTALL X MULTI WINDOW

Xposed is Framework for Rooted Android phone which allows you to change look and performance of your Android operating system and Android apps. you can add custom roms like features to your Android phone without installing a Custom rom, means you can make changes in stock rom. It in self does not do much but lets you install tweaks/apps/mods without using any custom recovery. you can change size of any increase or decrease window size of any app.

Requirements:

1.You need Android 4.0.3 or newer, to check your Android version go to Setting>About>Android version.

2.You need Root access on your phone

1.First of all download Xposed framework App after download completes Install it.

2.open the App and go to framework.

3.In framework click on Install/update and give Root access grant to Xposed framework.

4.wait till the installation gets complete, now reboot your device.

5.Xposed framework is now installed.

if you have any doubts, go to official thread.

It in self does not do much but lets you install many frameworks to improve your Android performance and look. open the xposed installer, there is variety of modules you can install any one of them. to install  choose anyone of them and click download.

It is similar to installing an App, it asks you for confirmation message. To start using Xposed framework go to modules and choose anyone framework from the list activate it. just reboot the phone to make the module working.

♦ Android Improved at 360º

♦ Graphics Improved a lot »Pure Graphic ™HD, Pure Dithering Plus™ and AOSPA 3.60 System

♦ Scan Multimedia time Drastically Reduced

♦ Network Improvements 3G experience in 2G  Modality

♦ All SQlite database optimized

♦ Enable hardware features turned off by default for a better experience on entry level devices

♦ Greatly increases the score AnTuTu→Try it to believe it!!

♦ Reduces the Startup time of Android

♦ Drastically decreased the drainage of battery

♦ Check the activities that consume too much battery stop them with PureWakelocks™

♦ When the phone is charging reduces system services for faster charging

♦ The battery is calibrated on every boot

♦ Disable animation of the system when the battery is nearly exhausted

♦ Improvements in build.prop as regards the part of consumption

♦ Enables a non-aggressive dithering to save CPU

♦ When you lock the device, the engine makes sure that the GPU is turned off

♦ Parts of Bravia Engine

♦ Parts of Cross Breeder

♦ Parts of Adrenaline Engine

♦ Pure Graphics HD

♦ V6 Supercharge

♦ Generates video entropy

♦ Slightly improves the scaling of the frequencies (Install Good kernel for Amazing Results)

♦ Lightens the load on the CPU switching the workload to GPU rendering

♦ Enable the swap partition in Android (Experimental)

1. Your Phone must be Rooted

INSTRUCTION

DOWNLOADS