The site uses a "community vote" to help moderation, so don't be surprised if the message is generic, and thanks for your patience in clearing things up here.

A lot of people probably didn't imagine you were an actual artist involved on EWJ. I looked the name on your profile on Mobygames, and it is credited on several titles, so personnally I would give you the benefit of the doubt (if you have any other public Internet presence, it would convince everybody).

Now about a more technical point : Pixeljoint's target is nice pixels, it even has +/- buttons for "clean" zoom x2, x3 etc. So you should submit the piece without any zoom, and especially no fractionnal zoom which leaves uneven pixels!
If the piece is too big and requires a smaller preview, this one should also be pixel-perfect : no resize with bilinear filtering! People usually submit a cropped part, with the word "preview" or "+" or a magnifying glass.
I'm sorry if it feels a hassle, but if you look recent submissions, you'll see these rules make everything very consistent for everybody, and the prettiest to browse.

Please note that even previews have to be pixelart.
Any CGd FX or anything not 'pixelled' excludes a piece.
If Jim is your creation then I don't see the problem cept without stating so many can just think you might have RIPed, copied and that is never allowed.