ya m here. ;p
Okay, if you wanna know my opinion about the image quality - it looks as good as it can. The image quality itself isn't a problem with it, per say. Problem lies in the fact that it looks tad over-sharpened - the hair and the right part of his coat, to be precise. Actually scratch that, on closer inspection, it looks as if the whole thing is over-sharpened. I'm sure that is what is giving it the little bit of pixel-y vibe that you probably noticed and hence asked for mine/Alex's feedback. I'm not sure if you cropped and saved the image from photoshop or not but I've had some works of mine in the past where they looked absolutely fine while I worked on them but ended up being over-sharpened when I saved them as pngs. There isn't really much you can do apart from maybe blurring out the parts that seem over-sharpened and try again. But that's a hassle and I don't really think many people will even be noticing it.
As for the icon itself, I think it looks okay. Feels a little squashed but that's definitely me. Colors are pretty. Positioning could have been a little better though, I feel. Anyway, you didn't ask for critique from a gfx person's perspective and were merely asking about the quality of the icon so I guess I'll shut up before I end up writing about all the pros and cons of the icon in a huuge para. lool