A Few Thumbnail Questions

[Blushock]

What are "high quality thumbnails", "embedded thumbnails", and "sharpened thumbnails"? The settings menu doesn't have hover text for any of them. Also, for embedded thumbnail, what is "Create from original image if embedded thumbnail is smaller than thumbnail size"? Thanks in advance.

[xnview]

"Embedded thumbnail"': Embedded thumbnail if it exists will be used
"Create from original image if embedded...": Often the embedded thumbnail is a small image, so you ask for a high thumbnail size, the embedded will not be used
"Sharpen thumbnails": it's to apply sharpen on the thumbnail