The documentation is a bit confusing - photo-slideshow mentions that you can use a USB, but first directs you to the tutorial, which doesn’t mention USB’s at all. Photo-gallery tells me that I have to set GALLERY_URL to USBDRIVE, but also says
Make sure to update CRON_SCHEDULE accordingly or else image changes will only be picked up at reboot.
But gives no guidance on what to set it to.
If I just set GALLERY_URL to USBDRIVE, the Pi screen says “Could not parse the album URL”, and the logs say No images found on views/usbstorage folder.
When I had mistakenly set GALLERY_URL to USBSTICK, the logs said error: Could not parse album.
the links you added and the errors are making sense here you see the GALLERY_URL indeed needs to be USBDRIVE
In the same repo there is an example what can be the value of the CRON_SHEDULE.
I set the CRON_SCHEDULE to 0 */12 * * * and views/usbstorage eventually reported having images, but I had to restart kiosk to get the images to display.
I’m not sure that setting the schedule was the cause, as server.js also sets the schedule to that value as a default.
I suspect that the usb has to be inserted after the pi initializes, and then takes some time to load them.