This is an IB bug that, well, bugs me:
If you add a portrait image to your asset catalogue and use it in an NSImageView, it gets rotated. The preview is fine, it’s fine if you add it to your project otherwise or load it from file; but from an asset catalogue, it fails.

Jun 22 2017
BugReports: NSImageView portrait images
This is an IB bug that, well, bugs me:
If you add a portrait image to your asset catalogue and use it in an NSImageView, it gets rotated. The preview is fine, it’s fine if you add it to your project otherwise or load it from file; but from an asset catalogue, it fails.
By Extelligent Cocoa • Bug Reports, Interface • • Tags: NSImageView