When you say “post” do you mean page? Hueman automatically shows a page’s featured image as the first image of the page and if that image has a caption, displays the caption in white over the image.
I fixed this by adding a child theme and removing <?php hu_get_template_part('parts/page-image'); ?> from page.php
Then you can add the image to the page as a normal image and control sizing in this way. I had a problem with gallery pages showing the featured image on the single page view on my website and this fixes it. You don’t have to worry about assigning classes to images as you upload them. Here’s my gallery pages as an example of this: https://tyler.provick.ca/gallery/
