I don't use Minimo, but I doubt there is a way to save a displayed webpage in it.
You can use FBshot to take a screenshot of the page... its a bit time-consuming, but it might do what you want.
https://www.mobileread.com/forums/showthread.php?t=15029
Be sure to download v2 at the bottom of the thread.
I've set my wait time to 90 seconds as I have to navigate through my CF card to browse.
If you want to, just change 30 to 90 in the file run.sh as follows:
$scriptdir ./fbshot -s 30
$scriptdir ./fbshot -s 90