Instagram API dynamically login

Instagram API dynamically login

I have 2 pages to allow user to fetch images from instagram index.php and
home.php
In index.php, provided login button to allow user to login.
<?php
$loginUrl = $instagram->getLoginUrl();
echo "<a class='button' href='$loginUrl'>Sign in with Instagram</a>";
?>
In home.php, it gets the code from the return url from index.php and get
the images.
My problem is, I dont want to direct user to login, I wish only 1 php page
to save my login id and password inside and dynamically login and save my
image to db by using only 1 page which means that to combine index.php and
home.php without using any button.
How should I do this? I am new to php and stuck in this. Please help and I
am really appreciate it. Thanks!