I usually like the lock screen pictures and like to have them as wallpapers, so I made this small script to copy them to Pictures/tmp. Running the script once or twice a week will usually grab all the pictures that have been used for the lock screen.
Just run the script from console
> python main.py
To save files to a different folder than tmp, just add the folder name at the end
> python main.py otherFolder
Package requires Python with Pillow installed. If you don't care, just run > pip install pillow after you have installed Python