As it is quite annoying as bug I just quickly made the fix to force rights on the file, it seems to work: 1st file that I uploaded was not visible, then I applied the fix and uploaded a 2nd file which was visible.
Should be ok for everybody, I hope.
If you notice pics having that problem (older vehicles pages, i.e. before the nr 270000) just report them, I can easily fix that on the server.