If that's the case, then it's kind of a lie.
First, the render already exists with the same effect (https://www.geforce.co.uk/sites/defau...-art-640px.jpg not the actual render but an implementation of it).
Second, it's not a decent render at all as it's surrounded by white parts...plus it's blurred.
The background is literally gimp's mosaic filter, while you merely added two color gradients and the text.
Plus, it's not an avatar. The ratio is wrong, unless you plan to use it on some weird forum, plus the size is simply too big.
Overall, the only thing i'd do to improve the image is to trash it and either start over or pretend you create it.
Overall, my score is abort/10.