John’s Background Switcher (簡稱 JBS) 是一款可定時 (如每小時或每天) 自動更換電腦桌布的免費軟體。您不但可以設定一次顯示一張圖片或多張圖片或拼貼圖，還可為圖片加上特效。尤有甚者，您可選擇從本機電腦、Google 圖片搜尋、Facebook、Flickr、Instagram、RSS、Vladstudio、500px、Phanfare、Picasa、Pixabay、Dropbox 等多個來源取得這些桌面背景圖片。
由於上述圖片來源大多需要授權或登入帳號，如果自己沒有很多圖片，建議可從 Pixabay 著手。這個圖片分享網站截至目前提供逾 54 萬張高解析度相片、向量圖與藝術插圖，任何人都可免費使用，甚至可用於商業用途。
注意：JBS 安裝伊始，預設為勾選所有它提供的多國語言，但您可只留下 Chinese (Traditional) 而取消勾選其他語言以節省硬碟空間。程式安裝後會常駐在系統工具列，只要在其圖示上按滑鼠右鍵即可叫出功能選單。
§ 作業系統：Windows XP/2003/Vista/2008/7/2012/8/10
§ 官方網站下載頁面
§ 檔案下載
John’s Background Switcher 原文簡介：
JBS periodically changes the background image on your computer (like every hour or every day) to something interesting. You can specify which pictures to choose from:
Individual pictures on your computer.
Folders containing pictures on your computer such as ‘My Pictures’.
Flickr photo sharing – selecting pictures by person, tags, sets or just plain random.
Facebook – your Facebook photos on your desktop!
Instagram – photos from the most awesome photo app out there!
Vladstudio wallpapers – choose from the coolest wallpapers on the net!
500px – the best high quality photography site on the web!
Any Media RSS feed – choose pictures from sites like DeviantArt, Photobucket, LOLCats and Tumblr blogs amongst many others!
Phanfare web albums – keep up to date with your friends and family.
smugmug photo galleries – yours, your friends, anybody’s!
Pixabay – the best place to find royalty free photos on the net.
Last.fm – see the music you listen to on your desktop!
Dropbox – your stuff, anywhere, and now on your desktop too!