Indeed, depending on the circumstances, the rules can be a little vague (e.g. regarding the use of add-ons or premade texture images). Over the years, we spent a lot of time discussing this and for now, it seems to be the best way of approaching this by taking the rules as guidelines and letting the artists decide (as they are the only ones who really know how an entry was created). 
(It doesn’t matter all that much, anyways.)
However, one of key characteristics of this challenge is the short period of time, in which everyone comes up with an unique idea, finds a way to translate that idea into an image and persuades all the vertices to hop into the right place.
So, all competing entries should be created for this challenge and within the set time frame. Of course, that doesn’t mean that images made for another occasion can’t be submitted. We have had a lot of these over time and most of them are very inspiring and a lot of fun to look at (like your butterfly lady above). But in order to keep things as fair as possible, these will be considered ‘non competing’ entries.
Not going to correct anything here. In fact, any new and substantial change to the image would probably work just fine. And after that, we will dive into the next round of our famous pure vs open discussion. (I’m just kidding… strike that… really… please, not again. ;-))
Looking at the time, I think, I should really start putting together some kind of entry…