It could mean that he likes you, but it could also just mean that he likes that particular photo. Now, if you have a bunch of photos of yourself on there and he "likes" all of them (and/or comments on some or a bunch)...then that would probably lean more towards him liking you. Do you know the guy or like the guy? If so, then "like" some of his photos and see what happens. I guess that would be "Facebook flirting"? I don't know. :)
It does not really mean that he likes you. This is because it could be that he likes your photo only. You should not get your hopes up just because he liked your photo. If you like him, talk to him so that he can open up to you.