Help, How can I rotate an image on screenshot before saving?

How can I rotate it?

 

There are few options:
1. Create new Texture2D with width and height you want, and copy pixels to that from the screenshot, then save it
2. Use native code plugin to create new rotated image and save it
http://forum.unity3d.com/threads/78853-grab-the-unity-screens-bitmap-data (orientation for rotating)
3. If image format supports it, change rotate tag.

 

#3, it's a jpeg, a simple screenshot from iphone. so how does the rotate tag works?

 

EXIF has Orientation Tag which can be altered with some tools.
http://www.leancrew.com/all-this/2009/04/derotating-jpegs-with-exiftool/
But I don't know if there is an existing easy to use tool for iOS.