I just got married in November and my photographer put a watermark on every photo even though it was agreed to ahead of time not to. How do I get rid of those water marks?
You need to understand that the watermark is not ‘levitating’ above the original picture information, but has replaced it. So whatever was in the place where the watermark is now, does no longer exist in the picture you have.
To ‘remove’ the watermark, you can use programs that copy data from nearby over it. Depending on the size and location, that can hide the watermark from a casual observer. But the real data that was there is not recoverable, if you don’t have the picture without the watermark.
Note - as others mentioned - there are potential legal issues with removing it. If you didn’t get what was agreed, you should be able to hold the photographer responsible, but acting yourself might well be illegal.
Simple: pay the photographer the agreed upon rate. He or she will then deliver on the agreed upon photos.
Can you remove the watermark? Well, if you have to ask, then you don't have the skill. And even if you did, it would most definitely be immoral and quite possibly be illegal.
I'm sure Dante would rank such an action right next to hypocrisy.