How to force Wine to open a png file by the default image viewer of my Linux system?

Solution 1:

First create a .reg file for example png.reg and type the following in it:

[HKEY_CLASSES_ROOT\.png]
@="PNGfile"
"Content Type"="image/png"
[HKEY_CLASSES_ROOT\PNGfile\Shell\Open\command]
@="/bin/sh run_linux_program gpicview \"%1\"" 

Then import the .reg file into the registry using

regedit [Address to your file]/png.reg 

for more information take a look at this. Please note that wine isn't installed on my machine so I haven't tested it.