I have an image saved from my game at
Application.persistentDataPath + @"/p.png"
If I need to write my own plugin does anyone have any decent documentation on how it's done?
That seems like the only way. Make a plugin that can read and write byte array to Picture folder on the
iOS. You can also use already made one from here that cost
$10. This plugins works with iOS, Android and Windows Phone 8 and I recommend you got with it.
The fact is that I can't write the whole process here. You first need to know how to write and read from the photo folder. Here is a link for that.
Now you need to know how to call a C# function fro Objective-C and vice versa. Many tutorials for this.
http://twnkls.com/2016/04/11/creating-native-plugins-for-unity3d/ http://alexanderwong.me/post/29861010648/call-objective-c-from-unity-call-unity-from https://www.quora.com/How-do-you-call-native-iOS-functions-from-Unity http://stackoverflow.com/a/30946257/3785314