まったく、小学生は最高だぜ!

到你的
Steam安裝位置\SteamLibrary\steamapps\workshop\content\431960
431960(代表WE的訂閱內容物) 裡面會有很多個子資料夾
431960----------------|

|---------------1409009311 (子資料夾A)
|---------------1324036699 (子資料夾B)
|---------------1409034200 (子資料夾C)
|---------------....
每個都對應一個壁紙，把你要備份的壁紙資料夾(假設是1409009311)
拷貝到

Steam安裝位置\SteamLibrary\steamapps\common\wallpaper_engine\projects\backup
（注意和上面路徑不一樣！！！）

裡面，所以backup裡面會有
|---------------1409009311 (子資料夾A)
|---------------....

projects裡面若沒有backup資料夾，就自己新建一個，
這樣就備份完成了。若取消訂閱，
則Steam會自動刪除431960下的1409009311 (子資料夾A)
但Steam不會刪除backup內的東西 :)

注意: 【被舉報的壁紙，Steam會自動刪除本地端431960內的壁紙】
所以建議喜歡的壁紙，務必手動備份。
注意: 當你移除Wallpaper Engine這程式時，backup可能也會被移除。
壁紙檔案請自行保管好~

以後發布壁紙，都會發布一份手動添加版的資料夾~


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When wallpapers are deleted from Steam for any reason, Steam will also delete them from your PC. Wallpaper Engine cannot prevent that, but if this is a concern for you, you can make a backup of your wallpapers.

Similar to that, there are many reports that Steam will randomly decide to re-download all Workshop files, which can be an annoyance if it's many GBs of data. Creating a backup and severing all ties to Steam can avoid that if it happens too often.
Creating a Backup

Steam stores all wallpapers in this location on your drive (depending on the Steam library where you installed Wallpaper Engine): C:\Program Files (x86)\Steam\steamapps\workshop\content\431960
Copy the folder 431960 to Wallpaper Engine's installation path here: C:\Program Files (x86)\Steam\steamapps\common\wallpaper_engine\projects\431960
Rename the folder 431960 into backup so you'll end up with this folder that includes all Workshop items: C:\Program Files (x86)\Steam\steamapps\common\wallpaper_engine\projects\backup


Restart the wallpaper browser and you should see the backed up wallpapers now. You can now unsubscribe the duplicate Steam ones and only use your personal copy of them.


💡 Pro tip: Do not just delete the original folder in Steam C:\Program Files (x86)\Steam\steamapps\workshop\content\431960 because this may confuse Steam and cause spurious downloading. It's better to unsubscribe them and let Steam delete the files

source: http://wallpaper-engine.wikia.com/wiki/Backup_Steam_Workshop