WebGL + JSLIB Plugin, how to pass images from JQuery to c#?

I've written a .jslib file in my /Assets/Plugins/WebGL folder that I am successfully calling it with my C# code (using [DllImport ("__Internal")] in C# ). The problem I am running into is the way how to pass the image back to C#. In the .jslib file, I am trying to get images using JQuery and wanted to pass them to C# code where the images will be used as the main texture for the game objects. I understand that the SendMessage could send string back to C# only. How could I send the image back to C# code immediately once the image is downloaded or cached successfully?