dpi is the standart measurement unit set by most graphic programs, dpi is also used by monitor measurment (even if the designer should say ppi) and yes it's definitly thought for print becaus of the print raster unit, but still the difference between ppi and dpi is for the common guy unkown and thous resulting in the saying "dpi for media is set by 72". and yes you are right it wouldn't lose sharpnes that was my failure of describing with a false word, what i meant is the pixel will be compromised and that will result in loss of pixel wich means that some details might disapear. and no if you resize a small picture from 300px x 400px with 300 dpi to ca. 600px x 800px and with the dpi value set smaller with half the size the picture will not lose sharpness because the pixel will not be stretched but relocated, but if you set a small dpi from the beginning and stretch it afterwards the picture will definitly blur