Rogue photos
Why does my wife's iPhone get photos taken on my iPhone but which do not show on my iPhone? We have separate iCloud accounts and are not logged in to one another's accounts. The only odd activity which may be relevant is that several times recently my new iPhone X has come up with a dialogue box inviting me to log in to my wife's iTunes account....which I haven't done and just ignored it.
iMac (27-inch Mid 2011), macOS Sierra (10.12.5), iPad Pro 12.9"; iPhone 6; Wifi; TV