You’ve probably seen the acronyms DPI, PPI, and LPI for resolution types. They all look and are similar, but the three are slightly different. Learning about and setting the correct DPI, PPI, and LPI ...
300dpi is generally accepted as photoquality. That's not to say you couldn't have applications where 300dpi wasn't enough, but generally this is so. 200dpi may be good enough for your mother. Start by ...