Cool! I had no idea MPC had that. But while a lot of controls are available, the "save thumbnails" actions doesn't seem to be one of them:
Does MPC Home Cinema have more controls?
If you're interested in updating your script so it no longer has to have focus for keypresses, MPC-HC
has been updated so that you can now Save Thumbnails from the Web Interface, (VIRTKEY 808).
Media Player Classic - Home Cinema 1.2.908.0
- Add VIRTKEY for "Save Thumbnails" (request #1964399)
For example, the following added to the web interface triggers the Save Thumbnails function:
<form action="/command.html" method="POST">
<input type="hidden" name="wm_command" value="808">
<input type="submit" value="Save Thumbnails" name="submit" onclick="postform(808,'null',0); return false;">
Or, you can now assign a hotkey to it so you don't have to navigate the menu.