I wanted to have a look at the GNOME icons at /usr/share/icons, and I expected Nautilus would be fine for this simple job.  However, Nautilus scales the icons, and there is no zoom level at which they appear clear, in their native resolutions.  I cannot think of any other test cases now, but I think that at least in this case it would be better to display small icons at native resolution and not to resize/upscale them.

See attached screenshot, which shows Nautilus and gThumb displaying these small icons.

PS.  I understand that in Nautilus 100% does not denote a zoom level, but rather a standard thumbnail size.  Even so, I think that, at least in this case, it makes more sense to display small icons at native resolution.

A relevant bug report:
Bug 463758 – small thumbnails should not get downscaled in normal view
http://bugzilla.gnome.org/show_bug.cgi?id=463758

Other information: