If you convert wmf to ps in a command line,it will be half the work with double results.
The command line which contains called program,source file and target file is very easy to learn.You should only know the path of called program and source file,then specify a suitable directory for the target file.
But at first,you should choose a converting software which supports the command line application.Based on this point,the software should be easy,fast and cheap at the same time.So HTML Converter is the best choice for you to convert wmf to tga format.
There are two kinds of VeryPDF HTML Converter software, one is a graphical user interface (GUI) application and the other is a command-line application. Most of users are probably accustomed to editing images one at a time with a GUI with such programs as gimp or Photoshop. However, a GUI is not always convenient. Suppose you want to process an image dynamically from a web script or you want to apply the same operations to many images or repeat a specific operation at different times to the same or different image. In these cases, the command-line image processing utility is appropriate.
You can download HTML Converter Command Line at the website https://www.verypdf.com/htmltools/htmltools.zip. There are the main information about HTML Converter Command Line at https://www.verypdf.com/htmltools/index.html. You can also read the user manual of the software by visiting https://www.verypdf.com/htmltools/htmltools-manual.htm.
You should register HTML Converter Command Line before using it to avoid the situation of some functions are disabled.
You can register the software like this:Run cmd.exe program and change the current directory to the installation directory of HTML Converter Command Line by “cd” command which means change directory.Then input the register code in the dialog box.
Then you can convert wmf to ps format.
First,run cmd.exe program by the hot key “Windows” + “R” and input “cmd” in “open” edit box of the popup dialog box,then click “OK” button.You can also click 
button and click “run” in the menu and do the same job mentioned above.
Second,input command lines in popup cmd.exe dialog box.The main command line is like the one showed below:
“htmltools.exe” “input.wmf” output.ps
If you don’t understand the command,don’t worry,we can take the command lines of converting wmf to ps as an example.
The commands are
"C:\Documents and Settings\admin\Local Settings\Temp\htmltools\htmltools.exe" "C:\Program Files\Microsoft Office\CLIPART\PUB60COR\AN00790_.WMF" 01.ps
"C:\Documents and Settings\admin\Local Settings\Temp\htmltools\htmltools.exe" is the path of called program which is htmltools.exe.
"C:\Program Files\Microsoft Office\CLIPART\PUB60COR\AN00790_.WMF" is the path of source file.
01.ps is the name of target file.
NOTE:
1.If you don’t want to input a so long path in the command line,you can drag the file you need into cmd.exe dialog box directly to save you precise time and the file will be changed into the path when being dragged into the dialog.You can try it yourself.
2.You can specify the path of target.If not,it will be saved in current directory automatically.For example,in this conversion you can find the target file in the folder C:\Documents and Settings\admin after you convert wmf to ps format.