How image resizing is working?

If you resize images in editor using visual guides (handles), the image will still be loaded in full size but with bad visual quality.
WP Meta SEO can resize/replace images in all your content, means that if an image is used several times in several articles, you can optimize all image instances.

Now you can replace and change in the dedicated place the good size of the image without changing the original one. Your website will be faster!