Wow, that's a real bautiful picture, as always. I can't seem to not like any of your pictures.She does look a bit sad, though. Probably the horror experiencing Pinkie's Pony Pokey. Or she is playing a rather melodramatic piece. Or she just had a sad day and plays the instrument to let out her emotions. Anythings probably works here.But since I'm a musician myself, I noticed two things:1) This one is quite apparent, but going to mention it anyway: The cello does not look right. I won't blame you. The proportions are wrong and the instrument is also lacking depth. But the details are very cool. The peg box looks more like the one from a contra bass though (maybe you actually wanted to draw that?) There are some other issues as well, for example that there is no fixed bridge on a cello (or any other of those instruments). They are usually just loosely put under the strings and are hold in place by the string tension only. And usually they are made out of much lighter colored wood than the painted cello. The neck is too long as well (in relation to the body). I could mention more, but I don't want to bore you and you can figure most things out on your own, if you want to. (And your focus wasn't on the instrument anyways, I assume)2) This one may a bit more important, but not quite as noticable. But that treble clef really does not look right to me. I remember a scene from university days, where an art class is drawing Octavia and the teacher says to pay special importance to her cutie mark, since it is not easy to get it right, if you did not draw treble clefs yet. But that's just a minor things as well, I think. Really depends on how detailled this should be or shouldn't be. It could also be, that this looked correct, when it wasn't cropped. (if it was, that is) It's hard to tell, really.Hope this is okay, that I mentioned those things.