tinyMCE editor setting localised path as src of uploaded image - tinymce

Question

I've setup tinyMCE to do image uploading and it displays uploaded images in the editor, but on inspecting the source of the editors HTML I can see that the src attribute is set like it would be a file path:
<img src="../../../api/images/1"/>
I have a file_picker_callback which POSTs the image to my backend server to save the image, and returns an absolute URL in the "location" key as specified in the tinyMCE docs: https://www.tiny.cloud/docs/configure/file-image-upload/#images_upload_url
But I am unsure why regardless of providing an absolute URL the src set on the image begins with "../../../".
The relevant tinyMCE configuration:
tinymce.init({
file_picker_types: 'file image',
file_picker_callback: function(cb, value, meta) {
let tinyMCE = this;
var input = document.createElement('input');
input.setAttribute('type', 'file');
input.setAttribute('accept', 'image/*,.doc,.docx,.txt,.rtf,.odt,.pdf');
input.onchange = function() {
var file = this.files[0];
var reader = new FileReader();
reader.onload = function () {
// Register the blob in TinyMCEs image blob registry.
var id = 'blobid' + (new Date()).getTime();
var blobCache = tinyMCE.editorUpload.blobCache;
var base64 = reader.result.split(',')[1];
var blobInfo = blobCache.create(id, file, base64);
blobCache.add(blobInfo);
backend.save(file).then(
fileLocation => {
let options = {};
if (meta.filetype == 'file') {
options = {
title: file.name,
text: 'My Attachment'
};
}
cb(fileLocation, options);
},
(/* error */) => {
blobCache.removeByUri(blobInfo.blobUri());
}
);
};
reader.readAsDataURL(file);
};
input.click();
}
});
I can see that there is an options object I can pass to the callback which sets some element attributes of the image, but I can't find a reference to what this object can contain in the docs :(
Would like some help to solve this and get absolute URLs in my image srcs, thanks

Answer 1

convert_urls: false,
By default all URLs are automatically converted to relative URLs. If you want to insert the real URL of the uploaded image, set convert_urls option to false. It will restore URLs to their original values.