You don’t even need any host to use the Nik plugins. They are standalone executables. You just need to launch the exe file, passing it the image filepath on the command line :
Silver Efex Pro 2.exe “D:\My Images\MyImage.tif” (quotes are needed when the filepath contains spaces)
Of course, doing this from the command line is rather awkward. But there are a lot of utilities that can make this process easier. For example, the Filemenu Tools provide a context menu command named “Run with parameters”. You just have to right-click the exe file, provide the parameter list (that is, in that case, the image path surrounded with quotes). The plugin will be launched.and your image will be loaded.
Typing the full path of the image is also cumbersome. No problem, Filemenu Tools also has a command for copying the path of a file. You can also use my Clipname utility to do that. You can get the 32/64-bit, FR/EN versions there :
https://www.dropbox.com/s/3kmylgajt6xglpr/Clipname64En.zip?dl=0
https://www.dropbox.com/s/1hnxou3sjf96nth/Clipname64Fr.zip?dl=0
https://www.dropbox.com/s/rdokyl8ta7mkxb2/ClipNameEn.zip?dl=0
https://www.dropbox.com/s/45xeyxjd4vokhx4/ClipNameFr.zip?dl=0
Using these tools, you can easily right-click the image file and copy its full path. Then right-click the plugin exe file, use the Run with parameters command and pass it the image path.
Another possibility is to merely create a shortcut on your desktop for each Nik executable. Then, just drag and drop the image on the shortcut’s thumbnail and that’s it. Or you launch the plugin by double-clicking the shortcut and then use the File menu to load the image.
Once your image has been loaded and processed in the plugin use the plugins File | Save as… command to save your edited file. Viveza doesn’t have a File menu, though. When you click save, your edits are saved to the original file which is overwritten (by the way, for the 110 euros I have already spent to support the development of the Nik plugins by DxO, I expected, at least, to get this oddity fixed).