Preferences

Select [Edit] Menu, [Preferences...] to show preferences window.

Fine shrinking (slower)
Better quality for shrank display.
This will slow display.
(There may no quality difference according to running operating system.)

Try to open unknown type files (slower)
Normally, image files are recognized by file name extension or additional information.
When this option is selected, Unfold tries to recognize image files by its content.
This will slow display.
(There may no quality difference according to running operating system.)

Auto scroll speed
Specify automatic scroll speed in pixels per second.