The difference between the two terms DPI and PPI is in what media it is used in. PPI is (Pixel Per Inch) for screens, and the measurement for the resolution when printing a image is DPI (Dots Per Inch).Dots Per Inch is a key factor when talking about print resolution. The more dots you have, the more detail you have. This also means that the lower the resolution of your file (digital image) is, DPI, the less detail it contains.The recommendation for hight quality images 300 dpi or more. You can say that 100dpi is acceptable quality from viewing distant 50cm and 200dpi  is good quality and 300dpi is picture perfect when printing. You can get away with a lower DPI for smaller prints but you’ll lose detail in larger prints.