Another method I used is Guides.
- Enable Guides. This option is found under View -> Guides -> Show guides
(Ctrl + Alt + E Ctrl + Alt + G)
Show Ruler. This option is found under View -> Show Ruler
Drag two horizontal guides and two vertical guides. Measure out their spacing on the ruler
Enable Snap to Guide. This option is found under View -> Snap to -> Guide
Resize image according to the guides