Comment 7 for bug 1066113

The clock is drawn on the wallpaper image and the resulting image ends up in ~/.config/variety and is set as desktop wallpaper. Again, if your permissions are ok, it will be used as a greeter (but the clock won't be updated while you are in the login screen, so I am not sure you want this - you'll be looking at an outdated clock on the greeter). The same thing happens with the other effects as well - they are applied on the original image, the result is saved in ~/.config/variety, and it is set as wallpaper.

It is true that the clock thread runs once every minute to update the wallpaper, but again I don't think this has anything to do with lightdm.

I will research whether it is possible to have the greeter and the wallpaper set to two different custom images at the same time (using the command above - gsettings set com.canonical.unity-greeter background "$1"). You can also help me with this part.

If this is possible, I can make the necessary changes so that it is possible to set the greeter to the wallpaper image before drawing the clock (but after other effects like blurring are applied).

If not, fixing this would require using some completely different way of drawing the clock on the desktop (ala conky), which I won't commit to doing for now, as the problem will be too small compared to the invasiveness of the solution.