On the page
https://www.accentcom.com/stmary/more-donors/
You will see on the more donors page that the images are different sizes. These are featured images which display.
And the text is of different lengths. These are excerpts which are below the main story text editor for each story (when you go to edit post).
If you make the excerpt too long it will break out of the box, so be careful and check your work.
It will be good to pick a category for each photo in the media library as you add featured images, so later they can be viewed by category.
I recommend you go in and edit as needed.