Open windows in the format in the screencapture, the browswer should be firefox
Search all
Limit it to videos
Open items missing thumbs
Play video until appropriate frame
Right-click the video and select "Take Screenshot"
Save screenshot in the "VideoThumb" folder listed below
jaccess\jp2\TransferFolder\VideoThumb 
It will have the correct name
check the thumbnail in the middle window on the left
Run the "JP2_from_JPG_CreateAccess.cmd" in the remote session
After black window closes, move the JPG to the completed folder
Monitor the extra large thumbnails in the window on the left to vary them enough that they appear different.