Garth, you are still overthinking. In 99% of all drawing you can ignore HiDPI. Just draw the 32x32 icon into the 16x16 picture.
Speaking of HiDPI I have not had to worry about it until recently, so I’m a bit fuzzy on it (no not a pun! 
)
Can image sets be used for menuitem icons so I don’t have to worry about swapping icons depending on screen scalefactor?
Also I think for Macs I really only need 1X and 2X images… But I gather HiDPI Scaling on Windows is not so straight forward … Do I need 3X for that or is that only for iOS?
For Windows I need to support Windows 7 and 10+
But for Macs, I need to support MacOS 10.7+ so I need to be able to also compile with 2017r1.1 which also means I need to be strictly API 1 - so I am coding with 2019r1.1
Were any Xojo HiDPI support changes made between 2017r1.1 and 2019r1.1?
Thanks,
-karen