photoshop encountered in the size of the image problem?

There are two pictures, their overall physical resolution is 800 * 600, and the format is the same, are JPG format:

one of the units is the resolution of 200dpi, is 4 inches high , Is a 3-inch width;
and the other a unit of the resolution is 100dpi, is the 8-inch height, width is 6 inches;

if the two pictures in the same display to display, or the same The printers print, the outcome will be the same as you?
If you do not like that picture goes better results???

In addition we would like to ask that some requests for electronic documents, photos inch of the unit is 150dpi resolution I know how she was required by the actual physical resolution images?? Is it to find an actual photo of an inch, they measured the length and width, and then multiplied by their respective 150dpi you?

2 photos are actually the same size
If the display shows that there is no difference, but if the printer, according to the actual print resolution, 100dpi images are 200dpi images play out 2 times the size of the 200 to make it clear.
E-resolution photographs of an inch 150dpi, you can PHOTOSHOP a direct cut in the crop size to set ah, the size is 2.6 inch of Cm x3.6 cm.Print when you look:in the chart and right – the election print size, you said I can tell you how much you want to look at the map, they do not tell the same size as, of course, the big Should be clear, size suit you?

One of the units is the resolution of 200dpi, is a 4-inch height, width is 3 inches;
and the other a unit of the resolution is 100dpi, a high degree of Is the 8-inch width is 6 inches;
that distinguish the great double, double the size of small! ! To clear when you scan large physical tell!