post https://{app}.{filespin}.{io}/api/v1/user/settings/watermark
There are two steps to update watermark with the optional first step.
STEP 1: to upload a new watermark (optional)
STEP 2: to update the watermark placement and scaling and optionally confirm the file uploaded in STEP 1 as the new watermark.
STEP 1(optional): Upload watermark file
Upload a image as watermark using multipart/form-data HTTP POST
Note that the uploaded file is not set as Watermark immediately and must be confirmed via another API call.
Watermark image must be JPG or PNG and must not exceed [1012px Width, 768px Height, 500 KB File Size]