How to Create a Blank Image of Any Size in Preview on Mac

Time needed: 3 minutes

To make a new empty image of any size in macOS Preview on a Mac:

1. Download a 1×1 pixel transparent PNG image.

   Roll your own: See below for creating the image yourself.
   Image size: A translucent image of any size works, of course; you can find examples below.
   Colors: You can also use a single-color image, of course, to create an arbitrarily sized colored image.
   Make it a template: You can have macOS automatically create a copy when you open the image so you do not need to duplicate it manually.

2. Open the file in Preview.

   Here’s how: You can always click on the file with the right mouse button in Finder, then select Open With | Preview from the context menu.
   Nothing to see here: You’ll not see much, of course; you can select all (using Command A, for example), to see the image in the center.

3. Create a duplicate of the original file.

   Here’s how: Select File | Duplicate from the menu, for example.
   Preview keyboard shortcut: You can also press Command Shift S (reminiscent of Save as…, which duplication essentially accomplishes).
   Not for templates: You can skip this step if you have made the template image stationery.

4. Choose a name for your custom-sized image under Name:.

   Using a template: With a template image, click the temporary name in the Preview title bar to open the naming pane.

5. Select Tools | Adjust Size… from the menu.

6. Turn off Scale proportionally.

   Equal proportions: You can leave it on for a square image, of course.
   Resampling: Do turn on Resampling so you can pick arbitrary image sizes.

7. Typically, change the unit to pixels.

   Other measurements: You can use the other units as well.

8. Enter the width and height in pixels under Width: and Height:, respectively.

9. Click OK.

   What now: Paste images to make a composite, for example, or to change a picture’s canvas size.
   Single-color: You can turn the new creation into a small, single-color image right in Preview.
   Their word: Apple include information on resizing images in the Preview User Guide.