Rate limit for media uploads

restapi
rate-limits
media-upload

#1

We manage campaigns for some high profile accounts and that leads to some very high burst of engagement. We are getting a rate limit when using the media uploader.
Is there a documented limit on this endpoint?
Is it different that the /update endpoint for sending a tweet?

It seems we are going to revert to an old school pic.twitter url in the message which reduces the content the client can send.