When I zoom a preview of a raw portrait image to 1x, it gets displayed as landscape and pixels are stretched accordingly, totally distorting the picture. If I slide the zoom down to 1/4 it's clearly been transformed to landscape.
No problem with RAW shots that are already in landscape, or JPEGs of either orientation.
I've tried having the previews generated from RAW or embedded JPEG and it makes no difference, they get transformed to landscape and stretched.
Platform: Mac OS X 10.5.2 PM 4.5.3