How do you post different pics on instagram?

[Tyt]

I see followers posting pics of music they listen to, or txt messages, and even incoming calls on instagram from their phone. It's like they had a another camera and took a pic of their screen and posted that way. I just didn't know if there was an app or if its an I phone feature? I have a Android.

[Megan]

On the iphone you are able to take a screen shot pressing the home and lock button at the same time. I dont know if theres a way to do that on the android phone? But as far as i know its an iphone/ipod touch feature.