A user made a list of the 都道府県 (46 out of 47, no idea which is missing). https://www.renshuu.org/study/... I went through it, and now they're all associated with a typical wiki map (Hokkaido and Okinawa are a little different). It would make no sense to do a def>kana quiz for this list (the answer is in the question), but now it would be possible to create a image > kana quiz. For the moment it might be the only such possible quiz, but if anyone is interested it could be possible to create other specialized quizzes (geography, anatomy...). Not a priority of course (I don't even plan to study the geography of Japan), just a an idea. Edit: the missing prefecture is Yamagata ken. If anyone wants to use the aforementioned list, they should manually add 山形県 to the schedule. I added the map to it.
No plans at the moment. Your example makes sense, but in MOST cases, unless you've seen the picture beforehand, it's going to be EXTREMELY hard to guess what word it refers to. Similarly, renshuu has no way to say "hey, this might also refer to x,y,z, so do not include them in possible answers".
I wouldn't want to make a new quiz mode, then turn around and say "it is not really good for most words out there, just these specific lists", especially when 90% of the quizzing on the site is through schedules =/.
If renshuu was a more guided study tool that told you what you should study (in terms of contents, like a textbook), this would be a better fit, but I'm not sure this is workable at the moment.