I was thinking about Zappy when I made this one! Put it on the site as a free image too, I was just sitting around going "Hmm I think Zappy would like a cute pic" so I sketched it in photoshop and it ended up looking good, so I coloured it too.
If there's something that I can point out, it's the weird spots of colour in the preview image. I've noticed that a lot of transparent PNG images have some colour a little bit outside the outlines. It's barely noticeable when set behind lighter backgrounds, but darker colours like gray and black (The latter I prefer to spot them) will make them much more apparent. It's not really important, but in any case it would help to place a completely black layer behind the rest, switch to whatever layers the colours are on and look for any areas where the colours appear seemingly out of nowhere (Which is actually the black outlines that separate the rest of the colour from out of their boundaries), then taking the eraser tool and carefully removing those 'renegade' splotches of colour. It takes a bit more time, but the result is a cleaner PNG for those who like their desktops/computer themes to be dark.
Sorry to bug you about that, it's just something that has been poking at me for a while. I have an example of how clean it can get which is uploaded somewhere else (You most likely know where ) It's still a great image, it's just when applied to a darker background that irks me.
The dots around the preview image isn't because of the colour outside of the lines, see for yourself, set your browser background to black and view the PNG in it. What's happened is that a white matte has been put around the preview.. like a gif file, annoyingly enough! It's one of the issues with gifs too, either you save it with a white matte and get that around the outlines, or you save it without a matte and the lines becomes jagged instead of anti aliased. That's why I decided to save it as PNG this time, so only the view is messed up and not the image XD