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no there is some creative thinking and you have a point, lol.
I think most of this is by hand. I'd start by using gradients for the BG. Then make light flares and put color on them. I'd use brushes that scatter dots, like confetti brushes. The lines on the right are just drawn/painted on. I'd go about making that sort of horse's tail by making paths and stroking them, duplicating them and moving them around and playing with opacities. Probably lots better ways, but that's where I'd start in a pinch!
The world has changed, in old days there were photographs and ways how to modify them, mostly in the dark room during developing, Sabattier's effect was the most magical thing and there was a thick line between photo and paint. Now anything can be created and the line is totally gone. New challenges arise :-D