[Milhouse]

WIll running this with argument 'C' cause XBMC to download and assign these new images as thumbnails and fanart?

It should do, as long as you see the correct thumbnail and fanart urls when you run:

Code:

./texturecache.py jd artists

then

Code:

./texturecache.py C artists

will forcibly re-cache just your artist thumbs.

do you know of some other way to achieve this with minimal manual effort?

Nope.