Update custom field IMAGE

Hi there,

am trying to use the plugin to update a certain image on a webpage.
The image is contained within a custom IMAGE field (created by ACF)

It is not working.

This url is tried to be added to the field:
https://[my_webpage_url]/index.php?gf-download=2022%2F02%2Fhomer_yellow4.png&form-id=8&field-id=1&hash=5ed26c61a472e494ff4f631795d2d8a874c5387bf9cf72816713e6a4d2e0daae

Why is the media not stored to the media library?

Cheers and thank you