How is image downsized when "Image is too big to fit on screen"?

When displaying an image in imshow, I get the error that "Image is too big to fit on screen; displaying at 67%" and I notice Moire patterns in the resulting image. I'd like to know how the image is downsized to display at reduced size. Is it subsampled, or something else?

Answer 1

[Steve Eddins]

Nearest-neighbor interpolation.

[KAE]

Thanks so much! This page has a nice demo of how nearest neighbor (and other downsampling algorithms) can introduce Moire, while some filtering beforehand can prevent it.