Insert image using Editor's image option:

<Editor
    style={{ marginLeft: "20px", width: "100%" }}
    dark={theme === "light" ? false : true}
    placeholder="Write something..."
    defaultValue={content}
    // defaultValue="Write something..."
    uploadImage={uploadPostImage}
    onChange={(v) => handleContent(v())}
/>

Resize and send image to server for uploading to cloudinary

const resizeFile = (file) =>
    new Promise((resolve) => {
      Resizer.imageFileResizer(
        file,
        720,
        400,
        "JPEG",
        100,
        0,
        (uri) => {
          resolve(uri);
        },
        "base64"
      );
    });

  const uploadPostImage = async (file) => {
    try {
      const image = await resizeFile(file);
      const { data } = await axios.post("/upload-image", { image });
      // console.log("UPLOAD FILE RESULT => ", data);
      return data.url;
    } catch (err) {
      console.log(err);
    }
  };

Image upload to cloudinary from nodejs

// route
router.post("/upload-image", requireSignin, uploadImage);

// controller
import cloudinary from "cloudinary";

cloudinary.config({
  cloud_name: process.env.CLOUDINARY_NAME,
  api_key: process.env.CLOUDINARY_KEY,
  api_secret: process.env.CLOUDINARY_SECRET,
});

export const uploadImage = async (req, res) => {
  try {
    // console.log(req.body.image);
    const result = await cloudinary.uploader.upload(req.body.image);
    console.log("uploaded image url => ", result);
    res.json({
      url: result.secure_url,
      public_id: result.public_id,
    });
  } catch (err) {
    console.log(err);
  }
};