POST
/pictures/thumbnails/preview-background-files/{instance_id}.png
curl \
--request POST 'http://api.example.com/pictures/thumbnails/preview-background-files/{instance_id}.png' \
--header "Authorization: $API_KEY"
curl \
--request POST 'http://api.example.com/pictures/thumbnails/preview-background-files/{instance_id}.png' \
--header "Authorization: $API_KEY"