I'm still not clear about this issue ...

When you speak of resolution, do you mean monitor resolution
... or do you mean image resolution? 

In order to check or change the monitor resolution you would show the desktop;
and then on an unused area of the desktop,

Right-Click -> properties -> settings ...

Please do that and tell us what you have there. 

OTOH, in Photoshop, you can set the image pixel count with

Image -> Image Size

Also in Photoshop, you can control the magnification of the current
workspace by using the key shortcuts 

Ctrl-Minus (Ctrl-) or

Ctrl-Plus (Ctrl+). 

HTH

--Martin