Change canvas size in Preview.app without scaling image?

I have a PNG that I want to add additional content to. For this I need to increase the canvas size of the image: Just make the image larger, but without scaling the existing contents (which the Adjust Size tool seems to insist on doing).

How can I do this?


This works well for me:

  1. Select all (cmd+A) and cut (cmd+X) the image from its canvas (convert to png if asked).

  2. Resize the image as desired from the "Tools" menu (unlock the proportions if desired)

  3. Re-paste original image from the clipboard (cmd+V) and move it where you want it on the resized canvas

  4. Use cmd+- if necessary to zoom out (you'll see checkerboard where the canvas is and white beyond)

  5. Paste in other images, etc, as you like


One option would be to Cut and paste using ⌘-ALT-X and ⌘V after resizing the canvas size in destination file. The pasted image doesn't seem to get snapped to canvas edges now.

Increasing canvas size by cropping doesn't seem to be possible.


The best method I have found is:

  1. Take a screenshot that is larger than your image you are working on, I usually take a shot of an empty text document so that it is entirely white.

  2. Paste your image onto the new image, and then add your other pasted image as well.

  3. Select the new combination image and copy it and make a final image by creating a new one from the clipboard.

This method only works if your two or more images are smaller than your screenshot image, but it works 95% of the time for me.