[Locked Duplicate Post] For Passport Size Photo Editing

For example I have a photo.

I need to make it passport size phot.

From phtoshop I have to make as follows :

1.   Photo border
2.   background color change
3.   photo editing
4.   Once I start dong is by Cntrl + N    measurement of width and height.
5.   What is the resolution need for Print photo in pixel.  I know resolution for screen is 300 pixels.
6.   Sometimes once I do item 4 the picture becomes very  smaller than I thought.
7.   Once I drag for printing sometimes picture becomes bigger than item 4.    Why?