Hi, I haven't made any plans to update for godot 4 yet, not quite sure what needs to be done for that yet. In the source code you only have to change the max value of the clamp on line 87 & 91 of GUI.gd
As an aside, 50k x 50k pixels wouldn't work unfortunately due to godot and system limits. See https://docs.godotengine.org/en/stable/classes/class_image.html