Photos taken using the photo app on mobile devices typically contain the orientation as EXIF data. The photo is not saved in the expected orientation by the photo app. Instead, the software has to read and consider the EXIF data to display the photo in the correct orientation (portrait or landscape).
When uploading a photo taking in portrait orientation to IBM Connections Files, the thumbnail image as well as the File preview will display the photo in landscape. Tested with IBM Connections 6 CR2 and IBM Connections Cloud.