As far as I know PrimopDF does not have an OCR element, so that all it would do is convert the jpg image to a PDF image - NOT a PDF with embedded text.
So while you have a PDF output file, you would not be able to index or search it.
If you just wanted to do that then you may as well use PDFCreator or one of the other free PDF programs
Yes it would create a PDF file (or series of files), but for use as an Ebook those files would be functionally useless