Photos you upload on Facebook timeline..?

[Hannah]

I'm new to timeline format now.. quite confused! I'm kinda photo-freak that cares a lot about how it's shown on profile than in album. I just made an album and uploaded about ten photos, and in my timeline it shows one big primary photo and 4 photos below it which I see it's normal? The thing is I just went to my friend's, and when he uploaded pics in an album, there's no primary pic but six same-size pics shown? How do you do that?
And I just checked old stories of my profile, it seems like there're these photos with the primary picuture above, and some albums just show about 6 to 9 same size photos.w hat's the difference and how do I manage it ? Anyone knows?