I love when I see images uploaded marked as "questionable" when there is plenty showing that leaves little to question.

A girl wearing a bikini. This is questionable.
A girl naked, barely covering nipples and vagina. This is not questionable.
Nipples clearly distinct, though not directly shown. This is not questionable.
Big cameltoe in your face. This is not questionable.

Have some sense, people.

First, lets be sure we know the basics:
http://konachan.com/help/ratings

Now, this pretty much covers all your cases above and clearly you're wrong.

There is http://konachan.net/ where only safe posts are displayed.

As long as genitals and/or actual graphic sexual activity aren't shown, there's an extremely large chance that it's questionable/safe.

Also, bikini posts like post #50289 are not questionable, just safe. Posts like post #58195 are.

Use your blacklist or the .net site.