推薦一款在Ubuntu系統下比較好用的截圖軟件Spectacle，現在已經正式替代了原來的KSnapshot。
After 14 years of being a part of KDE, KSnapshot has been retired and replaced with a new screenshot application, Spectacle.
https://kde.org/announcements/announce-applications-15.12.0.php
安裝Spectacle命令：
sudo apt install kde-spectacle