You might also try converting to PNG instead of jpg. Sometimes the file is smaller and the image quality superior, with fewer of the so-called artifacts (often, pale oultines around text or objects left by the conversion process) that jpgs can tend to have. The difference can be confusing, however; exactly why a file comes out better and/or smaller in a PNG than a jpg has stumped my colleagues and me; we can't determine why very similar files will convert quite differently between the two.