Foreground picture - sparing single slides

I am working on a slide show where I use a foreground picture as a “picture frame”. However the intro-picture and when starting a new chapter should be without that frame.

Is there a possibility to “switch off” the foreground on single slides only?

The only other chance I see is inserting a second layer with the foreground on twohundredsomething slides…

Any tipps an recommendations?

Thanks a lot for your ideas and support!