Many options are available for resizing your images on a Mac.  The recommended method is to use Photoshop or Lightroom when resizing for professional use or for physical printing.  Those two will give you the most options and the best results when it comes to resizing your images.  However, you may not own Photoshop, and even if you do, you may be looking for a faster option.  If you aren’t resizing for professional use or for print, then we recommending resizing with the “preview” feature on a Mac.  In this article, we’ll show you how to resize an image on mac with a quick and easy method.

When to Resize Your Images

Various reasons exist for needing to resize your images.  Here are some of the most common reasons:

  • You are uploading images to your website and don’t want to use up all of your server storage space.
  • You are uploading your images to a website with image size limitations
  • You want to send images to someone but the full resolution images are too large

How to resize your images on Mac | Step by Step

Step 1 – Find and Select The Images You Want to Resize

select all photos

Step 2 – Select “Open With” and Preview

Right click if you’re using a two button mouse.  Otherwise, double tap on your trackpad.  Then select “preview.”

open in preview

Step 3 – Select all of the photos you with to resize

Select all of the photos by clicking Command + a or hold down shift and click on the first and last image that you wish to resize to select all the images in between the images you clicked.

mac preview adjust size

Step 4 – Enter Desired width and resolution

The recommended size for your photos depend on your usage.  For most blogs, social media and other web use, 1200 pixels wide will be enough.  For web usage, a resolution of 72 is recommended.

how to resize an image on mac 72dpi 1200wide

What is “Scale Proportionally?”

If you don’t have this box checked, then the height and width of your image can change independently, or in other words, you could severely distort your image by stretching it or flattening it in either direction!

Therefore, leave Scale Proportionally checked, unless you want to actually warp your image.

With this box checked, you will notice that when you change one dimension, the other dimension is forced to change with it! This is a good thing because it is keeping your image’s height and width the same aspect ratio.

What is “Resample image?”

The box “Resample Image” needs to be checked if you want the actual size of your image to change. In other words, if you want to take a 24-megapixel image and output/save a 12-megapixel image, for example.

If you are preparing images for print, then it is always recommended to resample the image to fit exactly the correct dimensions of that print and whatever resolution the printer will accept. In some cases, this may even mean resizing your image to be larger!

If you are preparing an image to be displayed on the web, for example on social media or on a 4K display, then you will resample the image to a much smaller pixel dimension, such as a width of 3840px (4K) or 1080px (Instagram)

How to adjust an image, but maintain 300dpi

Many printers accept (or require) images that are 300 PPI (pixels per inch) in resolution. Usually, however, your image will not perfectly fit this requirement and will need to be resized.

If you don’t want to enlarge your image, and you simply want to see how large of a print you can make while still maintaining 300 PPI, then un-check the “Resample Image” box, and set the Resolution to 300 pixels/inch. You will notice that your image’s width and height is forced to change; this new inch (or centimeter) dimension is the largest you can make a print with optimal resolution.

If you want to make a print that is smaller than this, all you have to do is re-select “Resample Image”, and then set both the inch dimensions and the Resolution to match your desired print size.

If you want to make a print that is larger, you will re-select “Resample Image”, input your inch dimensions and Resolution, and your image will automatically be up-sized to fit what your printer accepts/requires, giving you a maximum level of fine detail in your printed photos!

Alternatives (besides Photoshop and Lightroom)

Screenshot – If you don’t need a high quality image, an alternative is to simply screenshot the image.  This is not recommended for professional use or for social media.  But sometimes, you just need to communicate something to someone via image and this sometimes the quickest way to do that.