I don't dock my phone with a PC...
I thought I had everything set to auto-backup to iCloud, but apparently not. I honestly don't understand any of this stuff. I just do whatever settings come stock and leave it at that because I don't know my *** from a hole in the ground here. It seems all my pictures/video save. So I really have no idea why my contacts don't...
Go into Settings, click on your profile listed at the top- maybe you’ve added a profile pic. Directly below your name it will read “Apple ID, iCloud, Media & Purchases”. Click that, then you might want to wait a minute for the phone to update/load info. Click on iCloud. In that menu you will see a list of toggles of what you’re saving to your iCloud account. If the toggle is green, you’re backing it up to your iCloud. If it’s not, it’s entirely stored on your phone.