LinkedIn Images API: initializeUpload, upload expiry and image status

To post an image on LinkedIn through the API, call POST /rest/images?action=initializeUpload with an owner URN, upload the bytes to the returned uploadUrl before uploadUrlExpiresAt, and then wait until the image status is AVAILABLE. The same image URN goes into your post. Sume can make the file; the upload dance is on your side.

What does the flow return?

The initialize call responds with a value holding uploadUrl, uploadUrlExpiresAt (a millisecond timestamp) and the image URN. The page lists the statuses PROCESSING, PROCESSING_FAILED, AVAILABLE and WAITING_UPLOAD, and notes that a downloadUrl returned on reads expires.

How should I schedule the steps?

Generate the image first and keep the bytes, since the upload URL expires and you do not want to regenerate on a retry. Then initialize, upload, poll the status, and only then create the post. A PROCESSING_FAILED status means re-uploading under a new initialize call.

• Generate once, store the file.
• Initialize close to upload time.
• Poll until AVAILABLE.
• Use the same URN for the post.

How do I make the file?

For a feed image, 4:5 or 1:1 in PNG or JPEG works. Request it from Sume Images and download it.

import json, os, urllib.request

body = {
    "model": "bytedance-seed/seedream-4.5",
    "prompt": "clean abstract header graphic in teal and white, no text",
    "aspect_ratio": "4:5",
    "output_format": "jpeg"
}
req = urllib.request.Request(
    "https://api.sume.com/v1/images",
    data=json.dumps(body).encode(),
    headers={
        "Authorization": "Bearer " + os.environ["SUME_API_KEY"],
        "Content-Type": "application/json",
    },
    method="POST",
)
print(urllib.request.urlopen(req).read().decode())

What should I verify?

Send the version header LinkedIn requires and check the API version policy. See the images guide for Sume's parameters.