I am not sure. I had always thought that it only selects the next predefined image size for the current resolution. But now I did an experiment with sizes 16 and 64 only, and it seemed to me that the images are always scaled correctly. However, I can only test up to 150%. And I have Win11 now, maybe this makes a difference - I don't know...
If intermediate resolutions are not handled correctly you should add them to the image list as well (16, 20, 24, 32, 48, 64). As I wrote it is enough to add only 64x64 images, and maybe 16x16.