It's a bit of a tricky subject. Lots of people are inspired by a style, but a palette swap or modification isn't really an original piece. I think that would be considered a rip here, which PJ doesn't allow.

Someone correct me if I'm wrong.

If you have an example, I'm sure someone could tell you whether or not it's acceptable. Post your sprite and the sprite that inspired you.

That looks fine to me but if I get nitpicky then the right ear is copied.
Being inspired by another is just fine but do not ever copy or RIP anything. Plagiarism is just uncool.
The better option is to get that inspiration and try to find your own take on it so that it retains what inspired you but still unique and original enough to feed your soul.
Giving credit or mentioning the inspiration ref for the art, colors or anything at all is always nice but in no way a must for most art sites and places. In pixelart its more common because its so much easier to nitpick. For example, you post your portrait to the gallery and don't mention the inspiration. Someone posts that the right ear is the same as 'vixels' work. Everyone else from then on gives you less credit and respect.
Lastly, on the technical side a res mix seems to go against this style (the mole on the cheek) and being super clean and crisp seems essential to the style and the lines on the collar in your piece is not that clean.

Oddly enough the ref is a jpeg but looks sharper than yours

Edited by jalonso - 28 March 2014 at 7:15pm