There is no hosting images natively on the forum.
If you already have on the internet, then get the link from that site and use the "image" button on the toolbar, post that way.
If you don't have a spot you already saved on the web, some people use this site
Imgur to upload their photo free, and then get the link and post it here.
This Is a Forum post that might be more in depth.
Welcome to the RVing Forums!
The RoadAbode Crew
Mike ~ Amy ~ Kimberly ~ Emily ~ and Molly the pup
RoadAbode Blog