I think maybe you could do this. What about the new, controversial DRM extensions? They're for video, but you could just show a 1 frame video on loop as an imag

I think maybe you could do this. What about the new, controversial DRM extensions? They're for video, but you could just show a 1 frame video on loop as an image, right? If those support HDCP then it's encrypted all the way to the display, and it would be challenging to screenshot it. (Of course, you could take a photo of the screen, but that's a substantial degradation).