I have Autoplay set up to import new photos from USB drives, and this has worked for years on my old USB stick. I've started using a new one, but it refuses to upload any of the photos to my Camera Uploads folder. I still have enough space left, and it offers me the chance to add the drive to my Backup (but this doesn't help me because I want the photos renamed according to the date they were taken). Camera Uploads still works for my Android phone, so it's clearly capable of recognising photos from there.