What steps should I take as a caregiver in this uncomfortable situation?

Posing for photos, Accepting Valentine's Day gifts, and being followed around while you work are not in your job description.

The fact that it makes you uncomfortable is reason to report it to your manager and be reassigned.

I was an in-home caregiver myself for 25 years. There were more old-timers than I can name here who liked to watch me clean. That never bothered me because I'd make them help. I'd tell them don't just stand there staring at me, clear the table. Or go get the vacuum cleaner. Or fold the clothes. There were a few that went beyond just leering at me bending over to pick something up that got physical and I defended myself. No one's putting their hands on me no matter how old they are and I don't care if they have dementia or not.
You should not have accepted the chocolates or the drinks. You call it the drink he buys for you so that tells me this is not the first time you've accepted.
How you should have handled it was to tell him that the agency doesn't allow aides to accept gifts, but that you'll have a couple of pieces of that chocolate and leave the rest for him so you don't get in trouble with your supervisor.
An absolutely hard NO on the taking pictures of you for any reason. Least of all "gossip". What do you think that means? You're 21 years old living in 2023 not the Victorian times where a young lady would have no idea why an old man wants pictures of them. Come on now.
You need to have a discussion with your client and tell him that the following you from room to room and buying you gifts is crossing an innappropriate line between client and caregiver. Let him know that you don't want to go to your supervisor.
I'll let you in on a little tip that you should do the next time you're assigned an old man as a client. Wear a wedding ring and tell them you're married.
Even when I wasn't married I did this. The old guys back off when they think you've got a man at home.

You know I think what is inappropriate behavior from the photos to the booze. Simply tell him so and tell him that you will not be able to work for him if it continues. He isn't a child and shouldn't be treated like one. It is also time to stop joking and kidding with him as clearly that isn't working well for him; act like a professional, and this is unlikely to happen, I think.

The taking picture...not sure if thats inappropriate because he did ask and you had the right to say no. "No sorry, don't like my picture taken"

The following you around would creep me out. Its called shadowing with Dementia. From day one I would have asked him to stop and I don't like it. If you are going to do a job like this, you set boundries from Day one. Your not their to make friends, your there to do a job. They are clients.

Hopefully Burnt Caregiver will respond, she is very good about placing boundries with her clients.

Your client is routinely crossing boundaries and you need to let your manager know. Don't second-guess what your manager will do to address the situation, don't elaborate on your client's intentions or motivations, just feed back the facts and act on the advice you are then given.

A drink every shift or so. Fine.
Chocolates once. Ok.
Photos? Could be innocent or could be too far.
You concented to 2 so that's done but stop it there so a habit does not form.

Any photos taken without your consent = assertively request they be deleted immediately.

An elder man can appreciate a pretty young lady but he may need frequent reminding what is ok & not ok.
Eg No touching rule. I need this much personal space rule. No photos rule. No gifts rule (a can of drink is an allowed exception).

I'd factor in his age, size & mobility when deciding on the risks to continue. A sweet talking (or even sleazy talking) frail older man confined to a wheelchair differs significantly to a physically able man.

In a care home, a physically able man with inappropriate behaviour may find he is assigned more male aides, or the female aides work in pairs. This is not possible for home care - so always keep your safety a top priority.

You should not return but might write him a note explaining your discomfort. Understand that many elderly people who have even slight dementia may have trouble with sexual impulses. (Thus the expression “dirty old man”). It is a brain problem and probably an emotional problem of loneliness too. You hear about it all the time- men pinching their nurses or trying to kiss them. Their impulses have weakened and they don’t even realize how inappropriate their behavior is.

Inappropriate requests by this client . Likely to escalate and if you refuse he may retaliate by telling lies and turning the tables on you . Don’t go back there. And speak up . I am a retired nurse who was afraid to speak up in the 1980’s about frequent inappropriate advances by the same doctor for years at the hospital I worked at . One Christmas Eve night I assumed he was gone for the day so I used the back stairwell. I ran into him and he pinned me up against the wall in the stairwell and kissed me . I was young and new to the job too. I regret not saying anything and wonder how many others he harassed after I left that job .

Trust your gut. This sounds creepy if not unsafe. I'd refuse to go back. You owe him nothing.

He’s crossed a line and is acting inappropriately. Let your manager know you’ll need to work at other assignments. And know it’s never wrong to speak up for yourself