Wordpress Remove Image Sizes http://www.wpmayor.com/remove-image-sizes-in-wordpress/

remove-size.php

function wpmayor_filter_image_sizes( $sizes) {
 
unset( $sizes['thumbnail']);
unset( $sizes['medium']);
unset( $sizes['large']);
unset( $sizes['wysija-newsletters-max']);
 
return $sizes;
}
add_filter('intermediate_image_sizes_advanced', 'wpmayor_filter_image_sizes');
 
function wpmayor_custom_image_sizes($sizes) {
$myimgsizes = array(
"image-in-post" => __( "Image in Post" ),
"full" => __( "Original size" )
);
return $myimgsizes;
}
add_filter('image_size_names_choose', 'wpmayor_custom_image_sizes');