How to add a css class to an img element

img src=“” class=“img-fluid” alt=“Responsive image”

const range = quill.getSelection(); quill.insertEmbed(range.index, ‘image’, ${url}); quill.pasteHTML(range.index, <img src="${url}" class="img-fluid" alt="Responsive image">);

[ModPhoenix]

var Image = Quill.import('formats/image');
Image.className = 'img-fluid';
Quill.register(Image, true);

[ModPhoenix]

var Image = Quill.import('formats/image');
  Image.className = 'img-fluid';
  Quill.register(Image, true);

  const quill = new Quill('#editor-container', {
    modules: {
      toolbar: '#toolbar-container'
    },
    placeholder: 'Compose ansdfdsfsdf epic...',
    theme: 'snow'
  });