I have not tried Skybox for my Quest 3. I assume it supports video files, via a USB Portable HD, but will it show STILL JPG Image files? Very annoying, as to get any image files on to the Quest 3 you have to connect the Quest 3 to a PC, then PC recognises the Quest 3, and then copy images from PC to Q3. A bit of a hassle. BUT then the image files are taking up valuable Q3 storage space rather than showing the image files direct from a portable USB storage.
4XVR does not support USB JPG, files but have said they plan to very soon. I am not paying for a VR Player that does not support JPG images.
