RGBlink VSP 628S User Manual page 105

In PIP mode, the default image1 is the main image, image2 for PIP sprite,
click the corresponding image when need to edit image1 or image2 , the
selected image with blue stripes, tick, as shown below: image2 is selected,
all settings will for image 2. For example, you can switch "Input" icon in
title bar to choose image 2 input source.
VSP 628S User Manual 105