I has set "Wallpaper Type" to "Slideshow" and added a folder containing many images, but the right-click menu has no the item "Next Wallpaper Image". Other functions work well, such as random changing images . Reproducible: Always
The same problem in Arch linux .
I found that the package Breeze will make the item "Next Wallpaper Image" disappeared.
In ArchLinux: if exists the file 1920x1080.png in /usr/share/wallpapers/Next/contents/images, the "Next Wallpaper Image" will disappear.
Git commit 2c8a82c30ee8c629a2cd699d5f44b3bdc299a96a by Marco Martin. Committed on 02/12/2014 at 18:21. Pushed by mart into branch 'Plasma/5.1'. add the next wallpaper action when necessary M +4 -3 wallpapers/image/imagepackage/contents/ui/main.qml http://commits.kde.org/plasma-workspace/2c8a82c30ee8c629a2cd699d5f44b3bdc299a96a
Git commit c35cbea3f48a32ffb4e7466398484aed3b7871f9 by Marco Martin. Committed on 02/12/2014 at 18:21. Pushed by mart into branch 'master'. add the next wallpaper action when necessary M +4 -3 wallpapers/image/imagepackage/contents/ui/main.qml http://commits.kde.org/plasma-workspace/c35cbea3f48a32ffb4e7466398484aed3b7871f9