What is the format of iTunes Artwork file?

Question

I am about to complete my mobile application, now i have to create iTunes Artwork file. I could not see any extension of the file in a sample i downloaded for reference.

How do i export my Vector image into iTunes Artwork file?

Answer 1

It's a PNG image without the .png extension.

Reference: http://developer.apple.com/library/ios/#qa/qa1686/_index.html