Crop an Image in Preview (Mac)


Need to add an image to your website, but it's too big?  This tutorial will walk you through the steps of cropping an image using the program called Preview, which is automatically installed on Macintosh computers.  You can view the tutorial for the Windows program called Paint here.  A common use case would be uploading banners to the announcement content type, which require that the images be 1180px x 346px.

Step 1: Navigate to the Preview program

You can find the Preview program a number of ways.  For some, it might be located in the dock at the bottom of your screen.  For others, you might find it in your launchpad.  As a last resort, you can open up a Finder window - click on Applications - and find Preview.  This is what the Preview icon looks like:

Preview Icon


Step 2: Select Image to Resize

Once you've opened the Preview program, go to File - Open in the menu bar.

Menu Bar

A browser window will pop up that allows you to locate the image that you wish to resize.

Browser Upload

Select the image and click "Open".


Step 3: Resize Image

When your image is open in the Preview window, go to the menu bar and click Tools - Adjust Size

Adjust Size in Preview

An "Image Dimensions" box will pop up on your image allowing you to adjust the size.

Image Dimensions

Change the size of the image and hit "Ok".  You can now save the image with the adjusted size.


Image Dimension Options

There are several options when adjusting the size of an image using the Image Dimension box.  You will notice that most of the time the image will pull up the size as a pixel.  A pixel is the unit of measurement used on the web.  You can change the unit of measurement by selecting the drop box associated with the width and height of the image.

Change unit of measurement

You can also change the resolution if necessary.  A resolution of 72 is ideal for web images.  If the image you have has a lower resolution than 72, changing it will not make the image any better, in fact, it will probably make it blurry.  Try to use an image that has a resolution of 72 or higher to begin with.  The same goes for the width and height of an should be a minimum size of what you will need it to be in the end.  Increasing the size of the original image to something higher distorts the image and reduces the quality.

The "Scale Proportionally" option should always be checked to keep the height and width proportional to each other.


That is all there is to resizing an image!

If you have problems with creating an announcement or have more questions about how to do any of the above, please contact Brian Webster or Kristi Elmore for help.