by Takashi SASAKI
It downloads 1x1 PNG image file and set it to the wallpaper. Thanks to http://png-pixel.com . It does not remain resident in RAM.
Improved: support lock screen wallpaper in a forked flow.
All of my flows are at http://jsrun.it/TakashiSasaki/wdGW .
Any question welcome at http://twitter.com/TakashiSasaki .
Rate and review within the app in the Community section.