How do I send a HTTP POST request with the image that the user picked from the image picker as the POST data?

How do I send a HTTP POST request with the image that the user picked from the image picker as the POST data? I am using the code from this expo susotirla to pick the image. The image is stored in { uri: selectedImage.localUri }. I know this because that is what a pass to the source part of the IMage tag.