Which sentence is correct?
The person in this photo says that he was in the wrong
or
The person in this photo said that he was in the wrong
or
The person in this photo says that he is in the wrong
There are two verbs in your proposed sentence that you are wondering whether to put in the present tense, or the past tense. Each should be chosen based on the appropriate tense for when and how the action they describe happened.
The person in this photo says that he was in the wrong.
That could be says or said. Is it something that have said very recently or are in the general habit of saying? Then it's the present tense, says. Is it something they said in the past, and are not in the habit of saying? Then it's the past tense, said.
The person in this photo says that he was in the wrong.
This could be was or is. Were they in the wrong about something in the past, but are either no longer in the wrong, or the matter is sufficiently 'past' that how they feel about it now has no practical effect? Then it's the past tense, was. Have they admitted to being currently in the wrong about some live issue? Then it's the present tense, is.