I wrote a little python script, that downloads a random astronomy picture of the day and then sets it as the desktop wallpaper.

When i was on Ubuntu 13.10 with gnome installed this script used to work fine, and i had it change my background via cronjob every few hours and it worked well.

However, now I have installed Ubuntu Gnome 13.10 and it behaves very strangely. The download works well, every time I run the script a new picture is being downloaded. However it only changes the wallpaper on the first time after a fresh start/ fresh log in. Starting with the second execution there's an ''animation'' on the desktop (turning blueish) but the wallpaper stays the same even though there's a different picture saved in my wallpaper directory. When i log out and back in again, the new picture appears as the wallpaper.

Does anyone know what may cause it? I've found this and implemented it, but it changed nothing. Also I think it is not related to crontab, because it also fails by manual execution.

The command used to set the wallpaper is the following

gsettings set org.gnome.desktop.background picture-uri file:///path/to/file.jpg

EDIT: The command above is the only relevant part, since executing it directly via terminal produces the same behavior.