Using GIMP: Correcting and Touching Up Your Images - GIMP 2.6 for Photographers: Image Editing with Open Source Software - page 84

2.3.5 Changing the Image View Size (Zooming)

You can zoom in and out on an image by using the Zoom Tool (Magnifier),
which can be found in the Toolbox. When you click the Zoom Tool , the cursor
will change into a magnifier icon. Clicking the magnifier on your image will
enlarge the image, and the spot where you clicked will become the center.
If you press the Ctrl button, hold it down, and click on the image again, the
image section will be reduced in size. You can repeat these steps until your
image has been reduced or enlarged to your specifications.
Alternatively, you can use the Zoom Tool in conjunction with the left
mouse button to pull a rectangle over the section of the image you wish
to select. When you release the mouse button, the part of the image you
“lassoed” with the rectangle will be displayed in the image window.

• NOTE
Changing the view size of your
image will not affect the actual
image or file size. The view options
customize how you see the image
on your computer screen, allowing
for easier editing and detail work.

Figure 2.22
The View > Zoom menu