Bug eye sparkle, the left eye (her right) is bulging out. It's really off-putting. I ended up recreating this picture using vectors found on this site to make a avatar for someone on canterlot.net forums who wanted this picture resized for his avatar. He agreed it looked better.
I NEEDED A SIMPLE PIC OF TWILIGHT SPARKLE TO FINISH A DRAWING I WAS WORKING ON BUT EVERY OTHER PIC WAS EITHER HUMANIZED/CARTOONIFIED/ANIME-IZED/ANOTHERANGLE/NOT NORMAL ENOUGH/I HAVE NO IDEA WHAT but thank you for this.
She's lovely here and looks like her sweet self. At first I thought she had a bit of a shy expression, but it really looks more like happiness tinged with some respectful silence. I imagine her standing in Princess Celestia court and being on her best behavior — following protocol for the sake of being official instead of the usual casual warmth they share. She doesn't mind one bit because she's always happy to be with her mentor, and showing respect is still very important to her.