Yes generally DPI is to control print quality. We must be careful to distinguish between Dots Per Inch (printer resolution), Display Pixels Per Inch (screen resolution based upon video card driver settings; based upon the defined number of pixels divided by the width of the display) and the absolute display resolution (a constant value, fixed by the hardware of the display; typically .22 - .25 mm between RGB clusters, therefore approx 96 PPI maximum). A 1 inch 300 dpi image will display as three inches of display width at the 100% size setting. A 1 inch 50 dpi image will display as 1/2 inch of display width at the 100% size setting. In order to display a 1 inch 300 dpi image as 1 inch of display width you (or the program) would have to create a temporary (so as not to damage the image data) down interpolation to the 96 PPI hardware limit. This is why "resize to fit" often introduces artifacts similar to those of the jpeg process.

Pass no temptation lightly by, for one never knows when it may pass again!