f = open("/path/to/file/screenshot.png", "r")
f2 = open("/path/to/file/screenshot2.png", "r")


data = {
    "type": "1",
    "photos": [
        {"image": f},
        {"image": f2}
    ]
}

print requests.post(url, data, auth=HTTPBasicAuth("usr", "pass")).json()