Weird Display Behaviour

I have just realised that when I change the wallpaper on my laptop it also changes on my desktop PC ... and vice versa

This never used to happen - anyone any ideas what's changed?

I don't know if it's significant but both computers updated to W10 Anniversary Edition recently.

TIA for any advice :)

If you're logging in with a Microsoft account -- that is, the same Microsoft account -- on both machines, it may be synching your themes and settings automatically across all those devices. That's been a feature since the inception of Windows 10 (and may even go back to Windows 8 or 8.1 -- I can't remember; indeed they do, according to the How-to Geek). This article explains how this works, if you're interested: Understanding the New Sync Settings in Windows 10.
HTH,
--Ed--

EdTittel said:

If you're logging in with a Microsoft account -- that is, the same Microsoft account -- on both machines, it may be synching your themes and settings automatically across all those devices. That's been a feature since the inception of Windows 10 (and may even go back to Windows 8 or 8.1 -- I can't remember; indeed they do, according to the How-to Geek). This article explains how this works, if you're interested: Understanding the New Sync Settings in Windows 10.
HTH,
--Ed--

Thanks for that Ed. I guess I must have changed the sync settings after the update.