as a rule the wallpaper files can be found in the folders below /usr/share/backgrounds.
This it true for the Cinnamon desktop. The xfce desktop puts its wallpaper files under /usr/share/xfce4/backdrops. (On my xfce system I see a symlink /usr/share/backgrounds pointing to /usr/share/xfce4/backdrops. The symlink date suggests that the Mint installer created the link, date of installation = date of symlink. But I cannot tell whether this symlink will be present on all xfce desktop systems.)
I do not know where KDE desktops store their global wallpapers.
Anyway, if you have still got access to a functioning Mint 15 system, you should be able to locate the global wallpers and simply copy them to a USB pendrive and from the USB pendrive to your Mint 16 system.
In case you do not have access a functioning Mint 15 system, you might use a Mint 15 live system instead and copy the wallpaper files from the live system.
You might also look for software packages here, Olivia
, that have got the string "background" in their names, download them manually and extract the wallpaper files which you like from the .deb installation packages. The software package "mint-backgrounds-olivia_1.4_all.deb" looks like a very promising candidate, in particular with respect to finding "Winter Fog".Looks as if the package "mint-backgrounds-olivia" should also be available inside the Mint 16 Petra software repositories. So you may forget all the hassle of all the manual approaches explained above and simply install "mint-backgrounds-olivia" from the Mint repos.