I'll have to look into that. I'm not quite sure what I would have to do though.
Well, I don't know about what you should do in a technical sense, I do not know Rempi completely. Being myself web developer, usually what is usually done is to put the images the alternative text attribute to be read by the screen reader. As I said, I don't know how that is done in Remppy, although I know you can because I have played visual novels in Remppy before.
The good thing about this is that the images are still there, so the people who see do not have to do anything new. A game that has applied this is recently Ravager by 4Minutewarning. He had the same problem, in this case with the map within the game, since everything was icons.