It seems like the only way to get approval for a Bot account is if it adds to or edits information already on Wikimedia. If you try to download any images, without a bot account
Didn't really find the answer I'm looking for .. but this page is interesting:: http://www.makeuseof.com/tag/4-free-tools-for-taking-wikipedia-offline/
Especially #4.. but it seems the page is down.. project dead?