To use this you will have to set the destination folder as the folder for your backgrounds (windows 7 go to Control Panel -> Change Desktop Background and change picture location)
If
New hot post in subreddit
This Trigger fires every time a new post becomes one of the ten hottest posts in the subreddit you specify.
Then
Upload file from URL
This action will download a file at a given URL and add it to Google Drive at the path you specify. NOTE: 100 MB file size limit.
Discover more time saving integrations for Reddit and Google Drive