Displaying the posts is simple enough, but I don't know of any extra that would save the images for you and remember which articles they belong to. If the WordPress program were open source, it could probably be converted to work with MODX, but since it's a commercial extra, that's not an option.
The tool you bought is a "Scraper." There is a series of blog posts about scraping and parsing on my Blog, which is exactly what you want to do:
https://bobsguides.com/blog.html/2017/10/23/scraping,-parsing,-and-api-use-i/, although it requires that you write some custom PHP.
You would have to identify the images, download them separately (since all you'll get are the URLs in the source), save them, and somehow store the association between the images and their respective articles. So --- not a trivial job.