WordPress – Set the maximum width of an uploaded image

In the following tutorial, I show you how to change the maximum size of an uploaded image in WordPress 2.5 and beyond. By default, when you upload an image in WordPress using the “full size” image option, the image is automatically resized to a maximum width of 500px. This works fine in most cases, for most people. However, if you are using a theme where your post content is utilizing a width larger than 500px, you may want to upload larger images to help maximize the space you have to work with.

How to set the maximum width of uploaded images:

  1. Login to your WordPress Admin panel
  2. Navigate to Design -> Theme Editor and select the functions.php (Theme Functions) file from the Theme Files list
  3. Just after the opening php tag, <?php add the following code (of course changing 800 to the max width you desire for an uploaded image)
  4. $GLOBALS['content_width'] = 800;

  5. Click Update File
  6. From now on, when you upload an image and insert it into to a post (using the “full size” option), the image will be resized to the maximum value you just set

Enjoy! 😉