Ive got a script you might find useful, I originally made it for vray but I just updated it for Corona. Not sure if its exactly what you are looking for but this is what it does:
Basically you can select a bunch of objects and press the button, it will find all the diffuse textures and show them in viewport. If it has opacity it will show the material instead (so you can see through the opacity in viewport). You might find it useful, often I have lots of objects that are just grey or whatever and just want to see all the diffuse textures immediately. Should work for both Physical/Legacy, CoronaBitmap and Bitmap.
Attached script.