I would like to set up the background so that I have a tiled image repeated. In
Gnome and Gnome Classic, I've set up an XML image for the wallpapers.

For the included screenshots, it looks like

<wallpapers>
<wallpaper deleted="false">
   <name xml:lang="en">256color</name>
   <filename>/path/to/image/256color.bmp</filename>
   <options>wallpaper</options>
</wallpaper>
</wallpapers>

The file was placed in ".local/share/gnome-background-properties" and shows up correctly in the "Appearance" and "Background" thumbnails. When selected in Gnome or Gnome Classic, it looks like the first screenshot, where the image has been Streched or Zoom or Spanned. The only difference is that the alignment is a little different. If Wallpaper is selected, which is supposed to tile the image, it makes no difference.

The tiling setting "Wallpaper" works correctly in "Gnome Flashback (Metacity)"