Preview, a built-in tool for every Mac user, has a powerful image editor that allows you to do a number of things. Today we’re going to focus on one of those features, the ability to shrink images down to size and keep them manageable for long term storage either in the cloud, or on your device. Please note, however, that before you delete anything that you’ve used Preview to shrink, it’s best to compare to make sure that the smaller image is still of a high enough quality to archive. If it’s not, it’s better to find out now, and switch to another compression setting, than it is to find it years later when it’s no longer something you can recover.

  1. Double-click to open the image in Preview.
  2. In Preview, open the File menu. 
  3. In the File menu, select Export.
  4. In the Export as dialogue box, move the Quality slider to compress the image to the required size.
  5. Click Save to save the new compressed file.