I followed docs on your site and used page folder to store images (_intro). Now I have a really hard time finding out how to get relative path of each images dynamically in my twig file. Also is it possible to access _intro folder images from modular.html.twig? thank you!
Yes, using folder paths like shown below. you can point any an images in the modular.html.twig file to the image location.
picture.jpg is located in the same folder as the current page
picture.jpg is located in the images folder located in the current folder
picture.jpg is located in the images folder located at the root of the current web
picture.jpg is located in the folder one level up from the current folder