Well, my other works are created in Inkscape without tracing. This one and the Background Tile, however are traces. What I did with them was take a screencap of the relevant scene, and paste into an Inkscape document. From there, I drew strokes to roughly match the curves and then cleaned them up until they looked polished to my satisfaction.
At that point, all I had to do was scale it up to where I wanted it to be and save it off.
If you want to give Inkscape a try, #MLPvectorclub has some good tutorials on the subject. There's also a connected group on Reddit that it's based out of. Inkscape is a free and opensource program, and I'm fond of it. I don't know with Flash proper, as I don't have that program, but if you grab Inkscape, Adobe Illustrator, or the like, you can open the .SVG I have for download and look at the components yourself if you wish.
I'm also more than happy to answer questions, even though I'm pretty new to all this myself.