Infographics don't prove anything. Just because some philosophers in recent years decided that believing that God "might" exist and that God "doesn't" exist aren't mutually exclusive doesn't mean it's true. It just means we've fallen to a deplorable state in our ability to reason.
The definition of Atheist is a person who disbelieves or lacks belief in the existence of God or gods. There's nothing in the (original) definition about whether they verbalize the possibility that they could be wrong in their beliefs. Ignostic is a very recent term (20th century) invented by philosophers who want to classify the idea that you have to define God in a way that you can falsify before arguing existence as separate from the idea the there is no God. This premise allows them to reject any concept of God that isn't falsifiable and falsify any concept of God that is falsifiable, therefore making it functional atheism.
And the classifications of "agnostic atheist" and "agnostic theist" are also recent inventions from philosophers who have no understanding of the fact that disbelieving and believing that there's a possibility are mutually exclusive. There are still people who accept the older, more logical school of philosophy that claiming no proof exists either way is simple agnosticism. And disbelieving in God, regardless of whether you choose to say that you may be wrong, is simple atheism. Atheism, agnosticism, theism, deism, and specific religious beliefs were all originally defined to encompass what you "believe," not whether or not you're willing to say that you "may be wrong."
An atheist who admits that he "may be wrong" or holds no position on the matter of the existence of God or gods is defined as a "weak atheist," (
http://atheism.about.com/od/Atheist-Dictionary/g/Definition-Weak-Atheist.htm). If they hold a belief that we just can't/don't know, then they fall under agnostic.
However, my initial post doesn't live or die on how you choose to classify somebody. Under the modern school of philosophy classification wording, an "agnostic atheist" or "agnostic theist" would still argue with the initial premise that we don't/can't know. Where as a "gnostic atheist" would argue from the initial premise that we do know and God/gods doesn't/don't exist, and a "gnostic theist" would argue from the premise that we do know and God/gods does/do exist.
And demanding a "falsifiable definition of God" is demanding making a god that's not really God. Because if God were falsifiable He wouldn't be God. Therefore, as I said before, this position that in recent years people have labeled "ignosticism" is functionally mere atheism.
Personally I believe that we can know, but proving is a different matter. Even if you've seen a bona fide miracle occur, an atheist or agnostic will either offer a different explanation or reject your experience entirely.