Very large (out of core) image viewer for Mac?
I am also looking for the answer to this.

I tried Xee, as recommended on the linked post, but it could not open the 2.43 GB ~1.8 billion pixel image from NASA's Curiosity rover (88797 x 22958 pixels TIFF image)

I have also tried Phiewer and ApolloOne, but they did not work for me either.

XNViewMP worked for me, but opened the file slowly, and basically freezes when I try to interact with the picture.