change image in webgl graph node

Drawing the initial webgl graph with image nodes works fine, but I cannot figure out how to change the image during runtime if the user e.g. interacts with a node. How are you supposed to do that?

Start from the WebGL graph-node rendering path that draws initial image nodes and trace how node interaction is exposed at runtime. Determine whether the existing rendering entry point supports replacing an image after initialization; done means documenting or enabling the runtime image change requested in the issue.

Written by the indexing model from the issue text.