Much sound advice above. All I would add is
a) Never use JPEGs for text or anything similar (such as music notation) if you can possibly avoid it. The JPEG format is designed to compress photographs, not things that are black and white with sharp edges. Use TIFF, GIF or PDF.
b) One other way of creating PDFs is to install OpenOffice, which is free and has a built-in PDF converter, and open the Word document in that.

Richard