Many cameras (particularly ones on smartphones and other mobile devices like iPhone) take advantage of shooting in HEIF or high-efficiency file formats. When those images are imported to Mylio we use available codecs or extensions on your device to create Thumbnail and Preview images for your library.
If you have HEIF photos or videos on your Windows computer running Mylio then both the HEIF Image Extensions the HEVC Video Extensions will need to be installed. Please know that in the latest Windows versions, HEIF Image Extensions are already installed and no further action may be needed. If you are seeing issues with Mylio generating thumbnails and previews for your HEIF images or videos though, see the links below the Microsoft Store.
HEIF Image Extensions: