To Bring One or More Images Forward One Place 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 Forward.
The selected image name(s) moves down the list by one position. Simultaneously, the view(s) in which the image(s) appears updates to show the new display order.