Remove default Image Sizes

Question

I'm trying to remove the default image sizes that are created given a specific image size threshold.

Listed using this:

get_intermediate_image_sizes() // thumbnail [1] => medium [2] => medium_large [3] => large [4] => 1536x1536 [5] => 2048x2048

I've found this method remove_image_size which doesn't work for the default ones.

I've found this snippet:

add_filter( 'intermediate_image_sizes_advanced', function($sizes){
    unset( $sizes['small']); 
    unset( $sizes['medium']);
    unset( $sizes['large']); 
    unset( $sizes['medium_large']); 
    return $sizes;
});

Which appears to do nothing.

Anyone got an idea as to how I'd go about removing the default image sizes?

Edit: The accepted answer is correctly how you remove the default image_sizes globally. If you'd rather want to switch between when different image_sizes should be active for which specific image assets then there's a way to do that here: image_size with respect to aspect ratios

Answer 1

To unset all default image sizes in WordPress using PHP you can use this function:

add_filter( 'intermediate_image_sizes', 'remove_default_img_sizes', 10, 1);

function remove_default_img_sizes( $sizes ) {
  $targets = ['thumbnail', 'medium', 'medium_large', 'large', '1536x1536', '2048x2048'];

  foreach($sizes as $size_index=>$size) {
    if(in_array($size, $targets)) {
      unset($sizes[$size_index]);
    }
  }

  return $sizes;
}

Alternatively, you can also unset default images by going into the WordPress dashboard. Then proceeding to Settings -> Media and put all value's on 0. See image for reference: