When I use the standalone image viewer and set the zoom level to 'Original Size' it is very clearly not the original size of the image. A 960 x 1280 image is displayed as 549x731 on my screen, and other images are scaled down similarly. I would expect 'Original Size' to be a pixel for pixel display of the image on the screen, and so I am wondering if this is a bug or for some reason by design.
I'm using Windows 10 build 1909, display scaling is set to 100% in Windows settings on a 1440p monitor..