I just connected my phone to my PC via USB cable and the options displayed for what to do with this device that included Import photos and videos using Photos or OneDrive. I chose OneDrive to see what would happen......... 2 hours later, the dialog changed to Importing photos and videos with a progress bar!
My suggestion is to provide more detail about the import process. The old import in Photo Gallery included a dialog for grouping photos by time period via a slider as well as an Options link to modify where they would be imported to, etc. I used to use that until it was superceded by OneDrive and Windows 10 apps.
My reason for suggesting this is because I do not know where the files are imported to AND I have already turned on Sync in OneDrive on my phone so they are imported to the OneDrive cloud service and synced to my PC automagically. The import function when I plug my phone in should be smarter and already know that syncing is occuring such that duplicates are eliminated and importing is coordinated between what can be stored in the cloud versus what is kept on the device. There is no option to "move" to the cloud to free up space on the phone so I am constantly having to move pictures and videos to another folder to get them off the phone. OR I am having to purchase another piece of software to handle this function.