推荐一款在Ubuntu系统下比较好用的截图软件Spectacle，现在已经正式替代了原来的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
安装Spectacle命令：
sudo apt install kde-spectacle