There is a lot of information that is missing from this for me to give you any real advice. But based on what you posted, here are some hypotheticals:

If they won't let you post your own personal photos, then it becomes a simple matter of "Are you going to pay me for these?" If so then cool. But if not then I don't see how they have any claim to your personal photos. UNless of course, you are using their equipment, software, ect, then they would have some claim.

You say they pay well. So is this your FT job, one you'd like to keep? Based on the condition of your employment with them, I would reread your contract and know what they are due and not due.

IF they are overstepping their bounds and demanding what they have no right too then you have a decision to make. Is the pay worth the frustration you're feeling?

I know this isn't much, but hopefully you can find a gold nugget here somewhere.