I think it was something similar to this technique which was used by JPL
to get some Mars Pathfinder pictures in "super resolution". They took
multiple pictures at slightly different angles and combined them digitally
to produce higher resolution than the camera was capable of.
The human eye is constantly jiggling. If you manage to stare at an
object without moving your eyes, it disappears. Using artificial means
to stabilize an image on the retina, it quickly fades to invisibility.
So it is conceivable that the eye could produce higher resolution images
than the spacing of its photoreceptors would imply.
Hal