I added options to set the thumbnail to hidden and one to resize the thumbnail. Resizing is not working, not sure why.
You can see changes here Manage folder and video thumbnails v0.5.0. Its beta, so test. I will try figure out the image resizing later.
NTFS changes the folder modified datatime if any file inside it is modified. I'm there are ways around this (using powershell and prob others) but its not something I would recommend.