Strech thumbnails to dial size

[Shinkoku]

Good day,
Is it possible to stretch thumbnail (taken from the "public library") to dial's size (I use dynamic dials with size set up manually)?
I tried all the settings I could find (dial settings/general thumbnail settings), but those public thumbnails are always small and fill only a part of the dial. Would like to stretch them, to fill entire dial or at least fit to height or width. That's be marvelous
Thanks for great add on!