I do it like this. In options rpy up the top look for
define config.layers = [ 'master', 'transient', 'screens', 'overlay' ]
And put over_screens between screens and overlay
define config.layers = [ 'master', 'transient', 'screens', 'over_screens', 'overlay' ]
Then when you want to use you type show image "my=image" onlayer over_screens
To hide it you need to type hide image "my=image" onlayer over_screens, or it wont hide
I got it from here a while back
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