CMS API upload images and multi-references

Hello, I would like to use the CMS api endpoint to insert an item that has a multi-image field , image field, and multi-reference field (provided in screenshot) I’m using developers webflow playground: Create Collection Item and I have the below

const fetch = require('node-fetch');

const url = '';
const options = {
 method: 'POST',
 headers: {
   accept: 'application/json',
   'content-type': 'application/json',
   authorization: 'Bearer  token'
 body: JSON.stringify({
   isArchived: false,
   isDraft: false,
   fieldData: {
     name: 'new post',
     post: 'hello',
     media: '[{  "url":  ""}]',
     coverphoto: '{  "url":  ""}'

fetch(url, options)
 .then(res => res.json())
 .then(json => console.log(json))
 .catch(err => console.error('error:' + err));

I’m able to get back a 200 response but I don’t see the images/multi-images uploaded. I also don’t know how to populate the membership multi-reference field via an api endpoint

for anyone in the future - I think I got it - it should technically work but I couldn’t use the webflow playground maybe because the field type is fixed to a string when the image takes in an object consisting of fields fileId, url, and alt

so I just copied the url and used Postman instead and copied this into the

body. fildId can seemingly be anything as long as it’s uniquely identifies the file/image
and then added my authorization token as well. Media field should be similar except just wrap the fields in an array. E.g. [{fieldId,url,alt},{fieldId,url,alt}]

    "fieldData": {
        "name": "test",
        "coverphoto": {
            "fileId": "6674bb47a976d71a85789c9bbf",
            "url": "",
            "alt": null