How do I POST an image file in my pipeline build?

I’d like to provide an image to POST during our azure devops release pipeline.This is the call:

I have tried to put the image in the working directory, which does share the file with my colleagues.
However, when make an API call to the postman cloud to get my postman script in azure devops: Screenshot 2019-12-12 at 08.01.50
the only artifact I receive is the postman script json. So after that, my upload picture post fails, since the picture does not exist in the pipeline. Is it possible to supply the image through the postman API? Or do I need to manually upload the image to the repo and link the script to that? How do other people test a file upload in their pipelines?