Setting image as wallpaper uses "Wallpaper mode" by default, not the default specified

[Patrik B.]

[Impact]

Setting the wallpaper scales it down incorrectly, not accepting defaults in system settings.

[Test case]

Open up Gthumb > select an image > right-click and choose "set as wallpaper" > image will be scaled incorrectly to wallpaper mode instead of the specified zoom mode.

This makes it very annoying to set an image via Gthumb but then having to open the tweak tool every time to correct the display mode.

Using other image viewers such as EOG doesn't produce this error.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: gthumb 3:3.3.1.is.3.2.8-0ubuntu2
ProcVersionSignature: Ubuntu 3.19.0-21.21-generic 3.19.8
Uname: Linux 3.19.0-21-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
CurrentDesktop: GNOME
Date: Mon Jul 6 09:46:14 2015
InstallationDate: Installed on 2015-07-05 (0 days ago)
InstallationMedia: Ubuntu-GNOME 15.04 "Vivid Vervet" - Release amd64 (20150422)
SourcePackage: gthumb
UpgradeStatus: No upgrade log present (probably fresh install)