How to change the WordPress default image sizes

If you’ve uploaded any images to a post or page on your WordPress site, you’ve noticed that WordPress offers to automatically scale down the size your images display for you. This can be handy — unless the sizes aren’t what you want them to be. When that’s the case, you have to choose one of the options, edit the image, and choose a custom size — an unwanted and unnecessary step. But did you know you can change the default image sizes in WordPress so it’ll offer the size you want out of the box? Here’s how to do it.

What are the default image sizes?

If you’ve uploaded images to a post of page before, you’ve probably noticed that WordPress provides 4 image sizes — thumbnail, medium, large and full size. The full size option is simply the exact size at which you uploaded an image and changes based on the image you upload, but the other 3 sizes are customizable. The default sizes are as follows:

  • Thumbnail: 150×150 square
  • Medium: up to 300×300 (tall images will be 300 pixels tall with a proportionately smaller width; wide images will be 300 pixels wide with a proportionately smaller height)
  • Large: up to 1024×1024 (based on proportion like the medium size)
  • Full: the original upload size

How to you change the preset sizes?

Go to Settings → Media in your WordPress Dashboard and you’ll see the default image sizes. Change the sizes to your liking and click Save Changes to apply them.

Also, be aware of two other settings. First, thumbnail images typically hard crop to square. You can turn this off by unchecking the “Crop thumbnail to exact dimensions” box. Second, you can choose whether or not your images are sorted into folders based on year and month with the “Organize my uploads month- and year-based folders” box.

The Media Settings page allows you to change the preset image sizes. Go to Settings → Media in your WordPress Dashboard to access these settings.

The Media Settings page allows you to change the preset image sizes. Go to Settings → Media in your WordPress Dashboard to access these settings.

Consider pixel-doubling your images

Because Retina and UHD displays are gaining rapid popularity, especially with mobile and tablet devices, consider creating your images at double the width and height of your display size. For example, if you set your medium image size to 600×600 like we use for the images at the top of our posts, create 1200×1200 graphics so they’ll look nice and sharp on pixel-doubled displays like 4K monitors or high-resolution phones. Learn more, including the display sizes you should expect your visitors to have, in our post about outdated websites.

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