tinymce-docs-4x/_includes/configuration/images-upload-credentials.md

images_upload_credentials

This option lets you specify if calls to the configured images_upload_url should pass along credentials like cookies etc cross domain.

Type: Boolean

Default Value: false

Possible Values: true, false

Example:

tinymce.init({
  selector: "textarea",  // change this value according to your html
  images_upload_credentials: true
});