In XnView and XnView MP support is needed for 256x256 and 512x512 page viewing of MacOS .icns icons.

The biggest .icns page that can be currently viewed is 128x128.
.. as you can see the same icon in that XnMP 0.26 screenshot is this one too which clearly shows the 256x256 and 512x512 pages
This issue is related to the recent 'Icon Snapshot' request-support for .icns written in related topic, here; http://newsgroup.xnview.com/viewtopic.p ... =15#p83601