How can I fix an “HTTP error” when uploading images?

There are a number of reasons why you might get a generic “HTTP error” when uploading images in the WordPress Media Library. The first place to look might be the resource limits in your /etc/php.ini file (memory and execution time, for example):

Some servers might also be running a deprecated version of ImageMagick. You can change the default image editor from ImageMagick to GD by adding the following filter to your theme (or child-theme) functions.php file (props mklusak).