Problem: “missing image file” when opening a Twinmotion project file on another computer;
Solution: Use “Resource collector” feature on the computer before saving your project file;

1. With project opened, go to Twinmotion menu bar > Edit > Resource collector;
2. Select destination path – ideally a folder on your regular file server;
3. You will end up with a .tm project file and a “maps” folder containing all the externally referenced files
4. You may need to re-link missing image files after opening project on the other computer from the maps folder;

distilled from: https://twinmotionhelp.epicgames.com/s/question/0D52L00003mmndTSAQ/moving-twinmotion-projects-between-computers?language=en_US