Implement a way to edit .PNG file after tagging

especially for an input image file ("fallback engine"), the need might rise to edit the picture, after tagging it

Currently we hand over the picture as an object, we should help the user save this object as file, and reimport it into the same array so the publish can function as usual.

This could either be described in the documentation, or another function (function of the object class that contains the figure + ID ? Although this might make it less generally accessible than an array)