The guy I like & I think likes me, doesn't like my pictures on facebook?

the guy i like i think has liked me back for like 6 months, he never told me but because he always looks at me and stares, looks back at me, fixes hair only when im there, eye contacts me a lot randomly, always turns to me, looks and turns when i walk by his locker, walks close and tries to get closer. we don't really talk though, we're in grade 9. anyway he got facebook at the ending of march and hes had 2 profile pictures and i liked both. ive had a couple of profile pictures since then and i didnt care if he didnt like them because i didnt think he liked peoples pictures, i just saw him like his guy friends picture. then i noticed he sometimes likes his female friends pix, theres about 4 of them and he doesnt like all of their pix but some. he doesnt act to them like he acts to me, he doesnt act like he could like them. i like a lot of guys pictures, theyre my friends, to me its the same as liking my female friends pic. but its pretty saddening.. why does he like his friends photos but not me, the person hes supposed to like? :(