Save an Image to Device Gallery on Smartphones

In my game, at the end of each level, I am giving some kind of images and things like that to players. Now, I want to give the players an option to save that particular image to their phone galleries. This is especially for smartphone users. How do I set the events such that the players will be able to save those images I provide them to their phone galleries? It is not a screenshot btw, it is a custom image that I prepared by myself on photoshop or some photo editing applications. So, how do I set the engine such that the users will be given the option to save the image on their particular device galleries? :slight_smile:

Anybody found my solution? :sob: