Adding a Product Image via PrestaShop Webservice API

Question

I have tried this to upload an image of a product to PrestaShop via its Webservice:

import requests

url = "http://127.0.0.1/prestashop/api/images/products/116"

payload = {'id_product': '116'}
files=[
  ('image',('20110101jpg-1.jpeg',open('/home/admin/Downloads/20110101jpg-1.jpeg','rb'),'image/jpeg'))
]
headers = {
  'Content-Type': 'multipart/form-data',
  'Authorization': 'Basic + ASDJJKHNKJASNDIAASDASD',
  'Cookie': 'PHPSESSID=6nhmk9jtmlta9r11f40g725cjk; PrestaShop-1c321b2b9a97944d3662932a96e7184f=def50200e83bedeaa690e780a78a450a6688a6aaafe245f6be864dcbe23aef85cfe6c178b21a25e652b8fac90b2af0a737d5668ba741a5faf523f6477121e4469f9928becfef69065d1afaccf437ea5b1900ec10c2799e13b05b3c9e1de2bcee3556af19b5d365d9d2c8f6dc7de5b98ed799f2a178a508fb2eede2cf4c49e5189988c04ed94b1a6ed9a6e7ebe9a7f8845341ccc9612ba27960d1bd28cf4299f32c7562420cb6399af72ee7f65c63d0557110daf03c586ad0b762d3920bde0a1d7d973ca4d1969ab836b038c64656753d89a3b5d7fb14510f9ab4e735cd740e192a1a09d79901263a08d3cf2d046e775bfcf27d84'
}

response = requests.request("POST", url, headers=headers, data=payload, files=files)

print(response.text)

But it returns this error:

<message>
  <![CDATA[Please set an "image" parameter with image data for value]]>
</message>

I need help debugging this issue.