Adding multiple background images with adjustable height

Hey everyone, so imma keep it short. I have a page where there is a textarea element present on the page with a single background image. HOWEVER, I need to use multiple background images which keep rotating as a slideshow in the background but whenever the textarea height increases the browser height, I want the background to stretch (or be magnified) accordingly.

When I add one background image as usual I can have desired result here the bg image magnifies itself whenever the textarea height increases but I need to add multiple background images instead of just one. Is there any way I can do so?

Hi,
If you haven't received an answer yet, you can post on some FB groups
+ Squarespace Customization Resource Groups
+ Squarespace Community
+ Squarespace Entrepreneur
+ Squarespace Rockstars