It'd be nice is the tags drop-down list only would only show good examples of tags (or give good tags priority). Ideally from an officially curated list.
As it is, it is flooded with the worst malformed tags which doesn't help matters any.
eg. trying to add a pixel art tag, an official pixel art tag should be first, should it be "pixelart", "pixel art", or "Pixel Art"?
The image also contains a Pokeball, the design of which should be subject to copyright and which I imagine could also be a trademark.
Most artists are familiar with "competitions" as a scamy way for unscrupulous types to try to get art for little or no cost ("If you enter your art we'll use it in our game!"). Doing such will likely have the opposite of the desired effect.
If you are really looking for talent, find artists with promising portfolio's and offer them paid art tests.
Just so people don't get conned, at least some (I suspect all) of the images in their gallery are simply bodged together traces of mismatched parts from copyrighted works.
The whole point of GPL is that it ensures that one cannot take the right to modify away from the user.
That doesn't require public domain. You can edit every submission on OGA.
Still looks very noisy, and more like grass with the odd blue flower.
You really need to increase the scale a great deal, even if that means doing so unrealisticly. Need to be able to see the individual crystals it it's going to be identifiable.
Also the colour is quite off from the sample image. Yours is very distinctly green whereas the sample is yellow and dark grey with only a hint of green to it.
I'm glad this threat isn't dirrected at me, I would surely be quaking in my boots at a legal threat from a sexually frustrated 14-year-old who doesn't understand that everyone's mother tells them they are special.
It's pixel art, specific software is irrelevant, any pixel art friendly image editor will do.