How to EDIT things image from API

Hello, I need to update an image for an object in the database through API for my app,
usually I do something like this to update text fields-

Request url-
https://myapp.com/api/1.1/obj/things/thingID?api_token=123

Payload-
status=doing okay

Now I need to update the things image field with an image, so simply replacing the payload with
image=https://realwebsite.com/image1.jpg
DOES work, and the image gets updated, but if I try to pass a local file like so

image=C:\Users\coolPC\Downloads\hehe.jpg

I get an error back -
{"statusCode":400,"body":{"status":"INVALID_DATA","message":"Invalid data for field stateimage_image: not a valid url or object"}}

I have also tried using
image=base64 encoded string

and the same error occurs, I am using urlencoded data type for these requests.

If someone has figured this out I’m all ears!
Thanks for reding :cowboy_hat_face: