You don't use Image Processor for print. It's impossible to batch-process the cropping/resizing/sharpening properly.
Image Processor is for web images, and for digital file sales. Not for prints.
But of course, your question is still a valid one. Files that you are sending to the lab do have to be jpegs. I talk at great length about the Image Quality setting for prints in the Sharpening Class, but as a general guide, Level 8-10 (on the 0-12 scale) is fine.