How can I shrink or magnify a photo displayed on the screen?

To magnify or shrink a photo, go to the bottom of the photo and press the ‘Actual Pixels(1:1)“ button or 'Fit to Screen Size'. If you want to magnify it to a specific ratio, then use the scroll bar and enter the ratio next to the ‘Fit to Screen Size' button. Similarly, you can press the Space bar and the Ctrl key at the same time. Then, the cursor will be changed to a magnifier with a (+) at the bottom right. Place your cursor on an area that you want to magnify. You can drag an area to magnify. Then the screen is filled up with the area selected. If you press the ‘Space' bar and the ‘Alt' key at the same time, it will be changed to a magnifier with a (-) in the bottom right. Click on a photo to shrink it.