Welcome to TSD from another newbie. It is amazing how much information the Den has, and if you can't find what you are looking for, just ask and someone will likely have the answer.
No restriction on posting photos based on length of membership that I know about. There is a limit on uploaded pictures - 1MB. You can adjust by cropping off edges, reducing the resolution, or saving the file as a GIF. Using your phone camera and texting the photo to yourself makes for generally acceptable image sizes. Other options include off site image hosting, or the free Tapatalk App. There's a playground for Post Testing that always turns into off the rails discussion.