Adjustable size screen shot in app

I would like to know if it is possible to make a screenshot within the app and allow to save it in photo album of the phone? Since i have too many things on the view, such as graphic buttons, few UIImages. And i want them all export or save as one picture.

However, i also want the screenshot to be adjustable. 开发者_如何学运维As there are many things i dont want such as the navigation bar etc.

May I know if it is possible?

Thank you all.