Hey, friend, A little question: did you cut that image from one already made for the series creators or you made it in Photoshop? I'm just asking because I want to make my own pony in one of those softwares. Thanks!
I took a screenshot of the show and opened it in a free open-source vector program called Inkscape. Then I used the vector software to create an infinitely scalable image. If you want to learn how to make vectors like this yourself, I recommend the tutorials in #MLP-VectorClub's gallery.