Although WordPress already gives you 3 default image sizes if you decide that these choices don’t meet your needs, there are alternatives. Maybe, you need smaller thumbnails or wider featured images. Therefore, you need to change the default WordPress image sizes. To do so, you can follow the steps below:

  1. Go to your Admin Dashboard
  2. Hover your cursor to Setting -> Media
  3. In the Media Settings window, you can adjust the desirable pixels for each size
  4. Hit the Save Changes button to save the setting.