If your Worksnaps client can't capture screen normally on Linux, such as the screen capture is black or partially captured. Please install the scrot command on you Linux, then run the Worksnaps client again.
Install Scrot on Linux
To install scrot on Ubuntu, Debian, or Linux Mint:
$ sudo apt-get install scrot
To install scrot on Fedora:
$ sudo yum install scrot
To install scrot on CentOS, you can build it from its source as follows.
First enable Repoforge on CentOS, and use the following commands.
$ sudo yum install giblib-devel
$ wget http://linuxbrit.co.uk/downloads/scrot-0.8.tar.gz
$ tar xvfvz scrot-0.8.tar.gz
$ cd scrot-0.8
$ sudo make install