Currently Being ModeratedJan 18, 2013 9:43 AM (in response to kelley33)
Do you mean originally a vector file?
Why rasterise it?
OSX's native files are pdf, which wil retain all the vector information. Pages will convert both .ai and .eps files to .pdf for internal use.
It is possible you have added some form of transparency to the jpeg file, this can cause it to be rendered at 72dpi which would account for the pixelation.