Straight guy at my work... Confusing signals.

SO yes it's one of these posts again, I know sorry. To anyone that's bored or ever been in a similar situation, I'm just looking for some enlightenment.I'm a 20 year old gay guy btw. I'm not totally out but not in the closet either, plus my younger brother is gay and more open than I. What I'm saying is most people assume I'm gay without asking anyway. So I'm guessing he knows I am.There's this guy at my job that's straight. He has literally said he is straight before and has had crushes on two girls at my work, one girl of which he texts still and wants to date I guess. He even asked me before if I though certain girls at my work were pretty? and to rate them 1-10 and I said I don't rate people. He's asked this more than like 3 times. To me that seems like a way to find out if I like girls or not.Anyway, my question is this if he's straight and obviously into females, why does he always talk to me and ask me personal questions? I'm a fairly shy person when it comes to meeting new people, but with him I never really was shy because to be honest he's not like a knockout in looks or anything. I never really thought I'd even slightly have a crush on him until he started talking to me a lot more.Some example situations are, one time he asked me my shoe size??? Which I was really weirded out by lol. I was working and he walks into my area and goes, "Hey how are you?" and I said good how are you?, and then out of literally nowhere, "What's your shoe size?" I was visibly shocked because that's, at least to me, not a question a straight guy would ask I would imagine? I mean I told him. I'm not some uptight douche it just caught me off guard. He said his reason for asking was because my "shoes looked small" and they should because I wear a small shoe size. I don't believe that was really the reason.He always jokes with me and tries to make me laugh, and I also make him laugh but I always make everyone laugh so it's not unusual for me. Sometimes he'll even half make fun of me in a joking manner to get a rise out of me and I retaliate playfully.When I'm working I swear to god it looks like he's sneaking photos of me. It could be in my head but I'm just throwing it out there. I even asked him before, so what are you doing? and he got awkward and said "nothing". I've been told straight guys look at my ass a lot by my friends so I would imagine he's taking pictures of me for that reason, if he is actually into guys at all. I can't see why else he would. Another guy I worked with took pictures of me from behind once, I got mad at him and he still took them anyway and had to add, "What I'm sending them to a girl" Like wtf why does that matter to me. So it isn't that far of a stretch to think something like this would happen again.He comments on my physical appearance sometimes. One time he and I were talking to someone about glasses and for some reason he said "but his eyes are big already as it is", because the glasses I tried on magnified my eyes. He's told me my hair cut looks good before. Asked me my exact height and weight... I talked about my chest hair once and he always brings it up now. He will sometimes even say "hey take off your shirt" and I just laugh. He says I love you when I'm leaving work and tell everyone goodbye... He's done that twice now.It just seems like whenever he's around me he only talks to me until someone else asks him something and he responds. Like when he asked me how I was today and no one else around me. 90 percent of the time, he's the one who initiates the conversation with me.That's about all I got. I know this post seemed sporadic but I tried to keep it as organized as possible. Honesty is appreciated, just looking for everyone's two cents here. Thank you for taking the time to read all of this!