It is so annoying the TinyMCE editor image plugin saving the height and width of the image. You can turn it off in the settings.

tinymce.init({
  selector: "textarea",  // change this value according to your HTML
  plugins: "image",
  menubar: "insert",
  toolbar: "image",
  image_dimensions: false
});

There are other settings available for the image plugin please visit here for details.