Is the 32 x 32 binary or could it be uint8() or could it be double() ?
You would not typically be able to preserve all of the information of a 640 x 480 binary image in a 32 x 32 array: if the 32 x 32 is to be binary it would require a compression rate of 300:1 which is not common at all for lossless compression. You should expect to be using compression that loses information. What kind of information about the image is it acceptable to lose?
To check: the 32 x 32 is to be data, right? Not an image itself? Data that could be used to reconstruct a 640 x 480 image? Because if the 32 x 32 is to be an image, that would be image resizing, not image compression.
When you say that you want 32 x 32: are you trying to construct feature vectors out of the 640 x 480?
