This is a custom bash script to automatically change the primary and secondary background colors in Gnome.
The script updates every second, you may need to slow it down to increase performance, I would not suggest speeding it up as it can cause high CPU utilization in Nautilus.
The script is intended to be used with a partially transparent background image, generally grayscale works the best.
To create a compatible background in GIMP.
1. Open the desired background image in the GIMP.
2. Set Image->Mode to RGB if it is not already
3. Desaturate: Colors->Desaturate (i usually choose the luminosity option but pick whichever looks best.)
4. Set 50% gray to transparency: go to Layer->Transparency->Color to Alpha, select color 808080
5. Export as PNG.
Will not work with Compiz backgrounds if you have disabled the Nautilus desktop for multiple backgrounds.
If you use a transparent panel, there may be a memory leak in gnome-panel which this script may accelerate, however this does not always occur.