Just added some .jpg-covers manually via iTunes (Song information => add cover) to my songs that are already loaded on my iPhone. These covers are shown correctly in my iTunes library now. Nevertheless my iPhone does not take over the new album covers.
I remember facing this problem some time ago and solved it by pasting the covers in once again. Nevertheless this time the approach does not work.
iPhone 7, iOS 10.0.2
You can try rebooting the device, but I suspect it won't make any difference. Removing the affected album and adding back may sometimes work, but it may be that you to take a more comprehensive approach.
The following steps should help with erratic syncing behaviour. They assume that all of the content you want on the device is in your library ready for restoring. If it isn't see Recover your iTunes library from your iPod or iOS device first. I would also recommend you copy everything out of the camera roll if you haven't already.
Use an encrypted backup if you want to preserve passwords, wi-fi settings, web history and health & homekit data where appropriate.
tt2
Covers manually added in iTunes not shown on iPhone
