This is an image of lightning or electric sparks? Well, I prefer lightning. I created this by following tutorial from here easy and here.

It is really easy tutorial and take less than 10 minutes for one lightning. Here I can confirm how much is render -> cloud is most useful future feature in GIMP.

I have use this render clouds in creating metallic brush effects. I would like to learn more about render clouds. Hope you can comment below, telling tutorial for me todo in process of learning render clouds in GIMP.

Besides, I also colour -> levels can remove unwanted rendered clouds and colour -> colourize -> will give your lightning colour.

That is all. Thank you.