I fixed mine from resetting by backing up first *for safety reasons* to /home/user/Documents/backups (I always make a backups folder)
the /usr/share/lxde/pcmanfm/LXDE.conf text file
then I deleted the /usr/share/lxde/pcmanfm/LXDE.conf text file.
Wallpapers started to stick after doing that for me. The $HOME/.config/pcmanfm/LXDE/pcmanfm.conf started taking over which wallpaper I had selected with my AntiX wallpaper.sh script that Dave wrote for AntiX. viewtopic.php?f=11&t=31202
Amrel RT 786ex 1.6ghz, 512MB ram , AntiX 8.5 core, Biker Linux user # 475019
Lead,Follow, or get the heck out of the way