I don't care how broad your definition is, it shouldn't include the mp4 files in my hard drive.
[0] https://security.stackexchange.com/questions/97856/can-simpl...
Also, you can convert your PNG images to Farbleld (+.gz | +.xz) without losing quality.
And the farbleld image format it's more difficult to exploit.
(At least, I'm assuming the question here is "What should Windows Defender do?" I agree that the answer to "What should OpenBSD's built-in antivirus do?" is "Literally not even exist," which it already does.)
Us power users can always just configure the exception list.
[1]: https://docs.microsoft.com/en-us/security-updates/SecurityBu...