WordPress at a glance
filter is not described

editor_max_image_size filter-hook . WP 2.5.0

Filters the maximum image size dimensions for the editor.

Usage

add_filter( 'editor_max_image_size', 'filter_function_name_3621', 10, 3 );
function filter_function_name_3621( $max_image_size, $size, $context ){
	// filter...

	return $max_image_size;
}
$max_image_size(array)
An array with the width as the first element, and the height as the second element.
$size(string/array)
Size of what the result image should be.
$context(string)
The context the image is being resized for. Possible values are 'display' (like in a theme) or 'edit' (like inserting into an editor).

Where the hook is called

image_constrain_size_for_editor()
editor_max_image_size
wp-includes/media.php 129
list( $max_width, $max_height ) = apply_filters( 'editor_max_image_size', array( $max_width, $max_height ), $size, $context );

Where the hook is used (in WP core)

Does not used.