Within the Publications page, you have option to add both preview image and description for each individual publications. Otherwise page will just show document with title, link and image icon. (Screenshot below with examples.)
Add Thumbnail (featured image)
Within Publication (Settings Sidebar), choose Featured Image. Select Set featured Image and select desired image from Media Library or Upload files.
Add Publication Description
Within each publication there is option (below Publication Title) to add a description. Otherwise the publication will display without using just icon.