No Image showing up with the all posts shortcode

Hello,

I added the all posts shortcode to my elementor page builder for my homepage and it shows everything except the image. I read the post, how to add a featured image , but I am not completely comfortable with going into the Theme Directory and editing in it that way. Is that still the only and up to date way to add a featured image (going through the theme directory) or is the a new/other to accomplish this. Thanks in advance.