In this blog it is explained that how to zoom in and zoom out images in photoshop.
Method 1
- open image in photoshop and select zoom tool from toolbox on left side.
2. click on image and it will zoom out or zoom in based on selected in top bar.
Method 2
- we can zoom in or zoom out from navigator on right side. if it is not displayed go to window->navigator in menu and check navigator.