<human>: Summarize the given text in a few sentences.

Some info: I'm 18, he's 14, and his sister is 17.

I went onto his computer to grab some movies off his hard drive. After, I wanted to quickly check my email because I was too lazy to get my Macbook from my bag. I type "h" into chrome to get to hotmail, and the autofill shows he has a tumblr with his typical gamertag. I won't post it here. So I thought, "hm, i'll look at it. See how many followers he has". It turns out, he has 2 blogs where he posts porn. One is "Hot Sex" and the other is "Cartoon Sex". At this point I'm staring at the screen confused. Since he's logged in, I see a third blog that's set to private. It has a picture of what I assume is a girl in his school. I found that picture on his hard drive titled "blackmail.jpg". So he distributes porn on tumblr and blackmails people, and that isn't all of it. Looking through his hard drive for more things, I find a folder titled "Breanna". In this folder is over 250 other folders with titles of what I assume are his facebook friends. Every folder was a photo album from his female facebook friends. Now it gets weirder. Back to his "Hot Sex" tumblr. The most recent post, from last week, is a picture of my other cousin (his sister) masturbating. The post text said "This is my actual sister, orgasming on video for her bf. I stole this from her computer." The video never played, it was just an image. This creeped me out the most. Keep in mind, she's 17. What i'm wondering is, can he get convicted of child porn at the age of 14? I'm still surprised by what I found.
<bot>: My 14 year old cousin posts porn onto tumblr, blackmails girls at his school, and posted a picture of my 17 year old cousin masturbating onto tumblr.