Image compression through vector quantization

When talking about vector quantization for compressing images, three steps have been taught to us so far: Codebook generation, encoding the image into vectors and decoding.

We have been taught to generate the codebook function which is basically going to take the vector from encodeImage.m as one of its argument.

My question is: Is there any command in Matlab which encodes the image? More specifically, how would you vectorize the image into specific bits of pixels? For instance, how would I compress the 8 bit pixel to 0.25 bits per pixel and vectorize it?

[FEBA SOMARAJAN]

Hey, hav eyou found any solution?