Without a sample link I could only guess they were using the theme’s columns feature (which is part of the presentation page).
But the texts can be disabled even from posts by filling in empty manual excerpts and changing the featured image size options to make it fill up the width of the post (it is currently only using part of the post width).
With the proposed solution I can make mi front page to only show an image, but there is another point.Can I make a brief summary to appear upon the image when the pointer is on it?