I doubt she is, but that doesn't mean it's real.
In my neighborhood, there is a highway underpass where a group of RC's have seen the picture of Mary in a water mark. They put flowers there, burn candles and "venerate" it. They have been doing this for over a year now. If you look at the water mark, you see a water mark. However, if you get closer and stand with a group of people who see Mary you begin to see things in the water mark.
The power of suggestion in an emotion filled group setting easily changes perception.
And that's goofy. What can I say, we got some goofy people same as every other group. There are a ton of so-called "apparitions" that are rejected flat out as natural phenomena by the local bishop--you don't really hear about them. The Madonna-of-the-underpass things you are talking about don't even get to that level.
The power of suggestion in an emotion filled group setting easily changes perception.
LOL...that's exactly what all the skeptics say. That's really a nice way of saying these people are stupid and/or gullible. And I dunno how the power of suggestion makes someone grow bleeding holes in their hands or smell roses.
Note that I'm not arguing all alleged supernatural events are supernatural. I'm saying you cannot dismiss an event as non-supernatural out of hand.