Just wanted to share with appgyver users that posting and retrieving images will not work unless you create an object list to store both the downloadURL and the storageKey. You can do this by creating a column with JSON data type in backendless.
For your reference:
And
After that you can create record. Formula is:
MAP(outputs[“Get bucket download URLs”].files, {downloadUrl: item.downloadUrl, storageKey: item.storageKey})
Hope that helps someone.