Can a page in Draw be saved in Pixels for the purpose of submitting a book cover to a publisher?
Your question is about output file format. Try menu File → Export ..., then choose a format from the drop down menu in the bottom of the dialog. You probably want BMP, but ask your publisher his preferred choice. Usually, for high-resolution typesetting, EPS (Postscript) is better because it is independent from the resolution of the flashing device (but it is not a “pixel” format).