To Bring One or More Images to the Front in the List

In the Raster Manager dialog, select the name(s) of the required image(s), or use the Raster Selection tool to select the image(s) in the view(s) .
From the Display menu, choose Bring To Front.
The selected image name(s) moves to the bottom of the list. Simultaneously, the view(s) in which the image(s) appears updates to show the selected image(s) in front of any other overlapping images.