Access file manager via Bubble API

I am trying to access/modify/manage some of the images I’ve uploaded to the file manager in my app via API. Is there a way to do this?
The aim is to replace some large files with smaller compressed versions as the original versions are slowing my mobile app down too much. As I’m using the multi file upload component, I can’t compress the images when they are being uploaded like with single file/image uploads. I’ve asked for help on another question to see if this is possible, but I haven’t had a response.
So I’ve built functionality in PHP to compress the image, so all I need to do now is get hold of the orginal image in Bubble via API and replace the contents with the new compressed version.

Did you manage to solve this by any chance? I’m interested in the same solution