Changing jquery plugin switching sliders (Supersized Jquery Plugin)

I have bought a wordpress theme which im pretty happy with. Only the seller doesn’t support customizations. So I was wondering is someone here can help me fix the issue.

This is what the seller said:

There are a few settings that can control the way the background images are handled, but due to the nature of screen-filling, responsive images, something has to give. That can either be squashed or cropped images, there’s no way to have full-background, perfect or uncropped images.

The background slideshow in Montreal is created & controlled by this jQuery plugin;
https://www.buildinternet.com/project/supersized/

See what you think by their demo page and examples. It sounds like you’re worried about the slideshow in Montreal; I cannot provide support for customisations so if you’re not sure, in the interest of keeping my customers 100% happy I might recommend Montreal is not for you. Purely because the last thing I want is for you to be disappointed! ?? That said, if you like the look of any of the SuperSized demos, and you can modify even the most basic jQuery, then you should be perfectly fine ??

Someone responded to hes comment with this:

I looked at your css, and noticed the same supersized jquery.. I looked at their demos and the Carousel one is responsive – it does not get squashed..

I believe you can provide support to fix this issue of slider not being squashed? Confirm this and I will go ahead to purchase theme… your presales customer support has been great and prompt so far.

here is the squashed screen shot of MONTREAL when in portrait mode – https://www.dropbox.com/s/ngf7mp2wxds7lq6/themesquashed.GIF

vs the non-squash version of the demo – same carousal
https://www.dropbox.com/s/jpo2rhv5dvdr5zo/nonsquashed.GIF

Than the seller replied with this:

Of course! ?? That’s as simple as a few settings in the Supersized plugin set-up. Rather than being an issue, this is simply how my designer chose for the images to be handled, it’s more than simple to modify this behaviour, again, it’s just part of the Supersized set-up ??

If you do buy Montreal let me know, & I’ll point you in the right direction. (Hint: the supersized set up is in page-home.php and is nicely commented, so you might not even need my help!)

I was wondering if anyone here can help me/put me in the right directions of how to set up/implent this slider.

https://stackoverflow.com/questions/19316616/changing-jquery-plugin-switching-sliders-supersized-jquery-plugin