This command adjusts the screen stretch of all images so that their brightness and contrast are equal. This is very useful when the images are to be blinked. Manual operations in the Align, Combine, and Mosaic commands are also eased, even though the final results of these commands do not depend on the rendering of the input images.
The Minimum and Maximum settings on the Screen Stretch window for the currently selected image are applied to all other open images, after being adjusted for the differences in background and dynamic range between "source" and "destination" images. This process depends on overall similarity of the distributions of bright, medium, and dark pixels in each image, and may not produce optimal results if their histogram shapes differ significantly.