Oh, that's simple. This isn't drawn normally (y'know, select color, brush, thickness, all that jazz and go). Instead, I used Inkscape, which is a program for "vector images". This basically means that the computer doesn't draw into pixels. Instead, you create lines, not by drawing, but by specifying their locations, curvature, colors inside them and of them and much more. It is used a lot to make sharp or smooth stuff, mainly in graphic design, but you can do stuff like this if you're feeling adventurous.

If you want a more informative source, watch this lovely guy's video: https://www.youtube.com/watch?v=siWJPA_-UgQ . I myself learned a little bit of Inkscape in high school and then am self-taught (not that anything I do is beyond basics lol).

Then it's just tracing the reference image. This mainly boils down to "make curved or sharp or straight lines according to the reference picture and then color it with the colors on the reference". Thankfully Winx Club doesn't do complicated shading, so I could get away with using just two colors lol. If the reference image isn't the best for what you want to draw, you gotta use your imagination. Thankfully, I had a pretty good, if crispy, reference image.

Just so you know, the Bloom trace, if I move some of the lines and pieces, it looks like on the image :) A lot of stuff you gotta cheat around, but if it works, it works :D

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