To open this dialog, click 
on the Image Registration Toolbar.
Image Registration Preferences
The Image Registration Preferences dialog is used to configure the image registration process. This dialog has 2 pages for setting preferences related to resampling the images and those related to setting the background of the registered images.
To open this dialog, click on the Image Registration Toolbar.
Other preferences related to drawing and placing
the markers are opened from the 
button.
This button opens the Marker Preferences command.
When you are finished making changes, click [Apply] or [OK] to accept the changes. Click [OK] to both accept and close the dialog.
Register Images, Tutorial: Introduction to Image Registration