The intermediate_image_sizes WordPress PHP Filter allows you to modify the list of intermediate image sizes.
Usage
add_filter('intermediate_image_sizes', 'my_custom_intermediate_sizes');
function my_custom_intermediate_sizes($default_sizes) {
// your custom code here
return $default_sizes;
}
Parameters
$default_sizes(string[]): An array of intermediate image size names. Defaults are ‘thumbnail’, ‘medium’, ‘medium_large’, ‘large’.
More information
See WordPress Developer Resources: intermediate_image_sizes
Examples
Add Custom Image Size
Add a custom image size called ‘custom_size’ to the list of intermediate image sizes.
add_filter('intermediate_image_sizes', 'add_custom_size');
function add_custom_size($default_sizes) {
$default_sizes[] = 'custom_size';
return $default_sizes;
}
Remove Large Image Size
Remove the ‘large’ image size from the list of intermediate image sizes.
add_filter('intermediate_image_sizes', 'remove_large_size');
function remove_large_size($default_sizes) {
$key = array_search('large', $default_sizes);
if (false !== $key) {
unset($default_sizes[$key]);
}
return $default_sizes;
}
Keep Only Thumbnail Image Size
Keep only the ‘thumbnail’ image size and remove all other intermediate image sizes.
add_filter('intermediate_image_sizes', 'keep_thumbnail_only');
function keep_thumbnail_only($default_sizes) {
return array('thumbnail');
}
Reorder Image Sizes
Reorder the list of intermediate image sizes.
add_filter('intermediate_image_sizes', 'reorder_sizes');
function reorder_sizes($default_sizes) {
return array('large', 'medium', 'thumbnail', 'medium_large');
}
Rename Medium Image Size
Rename the ‘medium’ image size to ‘custom_medium’.
add_filter('intermediate_image_sizes', 'rename_medium_size');
function rename_medium_size($default_sizes) {
$key = array_search('medium', $default_sizes);
if (false !== $key) {
$default_sizes[$key] = 'custom_medium';
}
return $default_sizes;
}