If you’re just dealing with a pixel buffer you’re filling out manually, you can use a simple linear array of pixels. GdkPixbuf provides that, but it also comes with a ton of code to load image data from various formats.
From that linear buffer, you can create GdkTexture instances whenever you want to draw it. There’s not much else you can do, because changing pixels requires resubmitting the buffer to the GPU.
That’s a very funny way to ask people for help. Let me know if it works out for you…