You can adjust the size of previews and change their appearance by hiding frame, title and author. In addition to that, you can decide how to display the contents of text files.
Open Application Wizard.
On macOS 13 or later, choose Application Wizard > Settings. On macOS 12 or 11, choose Application Wizard > Preferences. Then click Previews.
Drag a size slider. You can specify different maximum sizes for Music artwork, images, movies, PDF files, text files, and other files (Office and iWork documents, HTML files, ... ).
You can restore default sizes for all types of previews by clicking the Restore Default Sizes button.
Open Application Wizard.
On macOS 13 or later, choose Application Wizard > Settings. On macOS 12 or 11, choose Application Wizard > Preferences. Then click Previews.
Do any of the following:
To hide frames, deselect the “Frame previews” checkbox. Hiding frames reduces the global size of previews.
To hide titles and authors, deselect the “Show title and author when available” checkbox. Title and author are generally available for songs, PDF files, Office documents, and HTML files. Hiding title and author reduces the global size of previews.
By default, Application Wizard displays actual-size previews for text files. To switch to full-page previews, select the “Show full-size previews for text files” checkbox. Full-page previews offer a better overview of the contents of a text file, while actual-size previews provide a better readability and can be scrolled up and down.