Options - 'Bottom Panel'

Button 'OK'
Saves option changes and closes the window.

Button 'Cancel'
Purges option changes and closes the window.

Button 'Save as new style'
Saves your current settings under a new style name.

Button 'Reload File'
Reloads the preview file from disk.

Button 'Preview Format' and 'Preview Compress'
Shows you how your settings will work.