Alternative solution !!! 
Create a snapshot as usual of your VST plugin in Cubase. It will look bad but don’t worry.
Go to:
C:\Users[your user name]\Documents\Steinberg\VST Thumbnails
and sort the images to find the newest file. It ought to be your newly created snapshot. Just keep track of it and go back to Cubase.
Create a manual screen shot with windows print screen key (don’t ask me about macs, but there is some way, right?) and then use your favorite graphics program (M$ paint can do this) and paste the clipboard into a new document. Crop the image so only the VST plugin is visible and save the result in a *.png-file.
Now go the previous folder where you found the snapshot under VST thumbnails. Copy the whole name including the file extension and keep it in the clipboard [CTRL+C]. Delete the broken snapshot.
Go to your graphics program and save as the file name you have in the clipboard [CTRL+V] in the VST Thumbnails folder. If you prefer you can just save over the snapshot.
Now you have a nice looking snapshot of you VST plugin.
And nothing keeps you from using a photo of your mother in law for a distortion plugin … except your good judgement! 
Best of all. You’re now free to go back to do something better with your time, like play some music !!!