File View Options

Tools >  Options >  File Views

Thumbnail control for large files

Select Compress to fit to compress the thumbnail to the available vertical space.  Select Allow scrolling to show a vertical scrollbar instead.

Viewable in web browser

Specifies file types that can be viewed in a browser.  File comparison sessions will offer the Open with Web Browser command for these files.

Displayed files changed externally

Mark the Check for files changed on disk checkbox to check for a newer copy of a file when returning focus to a file comparison session.  If found, Beyond Compare will prompt "File changed on disk, reload?"  Mark the Automatically reload unless changes will be discarded checkbox to have BC automatically load the newer file as long as you haven't made changes to the displayed file.