What's up with all the movie photos released?

As much as I love seeing pictures from the upcoming Hunger Games movies, doesn't it feel like they're releasing quite a few of them? Especially seeing as they're still filming? And now there's a teaser trailer coming out this Sunday?? Despite my interest, I can't help feeling that it's a tiny bit premature.

We're seeing this a lot lately. The Twilight movies, The Hobbit, Snow White and the Huntsman. Is this a new trend in movie promotion/hype or has it been going on for a while and I'm just now noticing?

What do you think about this mini-spoilery? Does it seem like too much too soon, or does it help you get excited?