Hey there, welcome to Minitokyo! :)
Well, some scanners don't like their stuff shared in other places. They'll most likely write this in their
scan descriptions and/or userpage - though I would recommend messaging them and asking if it's OK to share their
scans.
"Edits" is a bit vague. If you mean making graphics (like wallpapers, icons, layouts etc.), then using scans
is fair game. If you mean editing the scans a bit (like removing text from them), I'd say that's also OK, but
you should still ask the uploader if the scans show up as Self-Scanned (you can see this in the upper right corner of
the scan's page, near the big thumbnail). However, you can't upload those de-texted/cleaned/etc. scans back to
Minitokyo, as we don't allow scans that have been modified like that.
(Moved your thread to Minitokyo Discussions, by the way, as it's more appropriate here :) )