File sizes / resolution

When you import files into Photoshop something interesting happens. They change their "size" (in relation to other files ) dependent on each file's resolution and dimensions. If I import a file that is 700 dpi it will appear as if it is huge if I started off working on a 300 dpi image.

My question is twofold. First how do see the resolution/dimensions of any given file. And second, What is the best way to make a file, lets say it is at 300 dpi and 3X3 inches, and make it the same size as a file with lower resolution and different dimensions?

Thanks!!

Gary

Thanks!

Gary