helper files to align tables/images [on hold]

I am very new to web design. I hacked a template for a simple page that has images on the left and text on the right. My site works well for web-sized browsers, but it does not align for mobile/minimized windows.

Behavior of the original site: when minimized the image goes on top, text goes on bottom Behavior of my site: when minimized the image remains on the left and text remains on the right, so I need to scroll right to read it.

The problem does not seem to be with html, but with helper css and js files. Which ones do you know of that help with table alignments?